How we research, and how comparisons are ordered
Every material figure on this site comes from a named source with the date we read it, and you can open that evidence next to the figure. Where we calculate something, we say so and show the assumptions. Below: what we cover, where figures come from, which source wins, how often we recheck, and how providers are ordered.
The one that matters
Commercial payments never affect the order of a comparison. If we could not keep that promise for a table, that table would carry the reason instead of the promise.
Stated flatly because it is about our own conduct, which we control. Claims about the market are scoped to the sources we examined and the date we examined them.
What the register covers
Every proposition we have identified and researched, sorted into segments that decide how each may be used. A specialist or private-banking proposition is never ranked against a mainstream one, because they serve different customers.
| Segment | Count | How it is used |
|---|---|---|
| mainstream | 3 | Regulated owner-occupied HPP for ordinary UK applicants. The default comparison. |
| specialist | 3 | Regulated, but different customer scope (residency, wealth, geography). Shown separately, never ranked against mainstream. |
| private-bank | 1 | Relationship-banking product. Directory listing only, no rate comparison. |
| legacy | 1 | Existing-customer servicing; no verified new-business route. |
| alternative | 2 | Not a regulated HPP. Separate section with explicit warnings. |
| not-relevant | 3 | No verified UK retail owner-occupied proposition. Excluded from provider counts. |
Not exhaustive, and not for sale. It is every proposition we have found and can evidence, not every one that exists; broker-only ranges and new entrants are the obvious gaps, and if you know of one we are missing, tell us. Inclusion depends on evidence, never on a commercial interest or relationship with us.
The four availability classes the ordering rules use
Segment says which comparison a proposition belongs in. Availability says whether we have established a current route into it, and a proposition can be specialist and open at once.
Open: a verified current route for the relevant customer and product. Waiting list: a route exists but access is queued or constrained. Not verified: we could not establish a current new-business or retail route. Unconfirmed: unclear enough that we will not rank it as open.
These counts are generated from the records that build the site.
- 13
- propositions tracked, including ones not open to ordinary UK buyers
- 64
- registered sources, across 15 organisations
- 48
- canonical facts, each with a source and a checked date
- 7
- facts where a provider's own sources disagree
- 21
- open questions we have not resolved
- 118
- dated entries in the change log
On those open questions. None of the 21 has yet been raised with the provider concerned. We record what we could not establish and why; we do not yet operate a provider-response process, and we will not describe one until we do.
Where figures come from
Provider primary documents first: rate cards, product and criteria guides, tariffs of charges, certificates. Then provider public pages, the FCA Register and Companies House, and official statistics such as Bank of England series. For every material figure we record the source, the date we read it, and enough of the wording to check us.
We do not use other comparison sites as sources for figures. A copied number arrives without its evidence and carries their mistakes into our records.
Published figures, derived findings and worked examples
Not everything here is a number a provider printed. There are three classes, labelled differently because they carry different weight.
- Published fact
- A provider or official source states it directly: a rate, a fee, a deposit tier, a criterion.
- Derived finding
- We calculate it from two or more sourced records, each keeping its own source and date. The result is ours, not the provider's: a gap against a benchmark, a count of products meeting a condition, the difference between two deposit tiers.
- Worked example
- Arithmetic on stated assumptions, shown with the result. An illustration, not a quote, an affordability decision or a claim about the market.
Why a derived finding needs more than good inputs
Two correctly sourced numbers can still make a false comparison. A provider rate observed in August set against a benchmark observed in April is a gap between two months, not between two products. So a derived finding carries its inputs, both observation dates and a vintage classification, and a build check fails if any of those is missing.
What a figure can be
Published or absent is not enough to describe this market honestly, so figures here hold one of 5 states. The counts are live.
| State | Count | What it means |
|---|---|---|
| Confirmed as published | 37 | One source, read directly, saying the thing plainly on the date we read it. It means the provider published this, not that it is guaranteed to be the decision an underwriter reaches on an individual application. |
| Disputed | 7 | Two or more first-party sources publish incompatible values, conditions or rules for the same fact. We hold every published version and treat none as governing. |
| Unresolved, multiple observations | 1 | Several published statements that are not competing readings of one number but observations about different things. Each keeps its own scope. |
| Not found in reviewed sources | 2 | We did not locate it in the sources we reviewed, on the date stated. Finding one document proves a thing is published; not finding it does not prove it was never published anywhere, so this state says what we can support rather than more. It is still never treated as a permission. |
| Blocked | 1 | The figure exists but we could not read it, for example a rate that renders as 0% to an automated reader. We publish the obstacle, not a guess. |
Why "disputed" is a state and not a decision
Taking the newer value, the one that reads like a summary, or the lower one because it is safer are all guesses dressed as judgement. A disputed figure is shown with every value the provider publishes, and separate code decides what an eligibility check may rely on, so a display can never quietly become a decision.
Product scope, and why it has its own rule
One provider can run a home purchase plan, a buy-to-let range and a bridge product, each with its own criteria, and the buy-to-let criteria are often the easiest to find. So every source carries the product it speaks for, and a home purchase plan page cannot be built on buy-to-let sources. Where a tempting figure exists for another product, we show it and say why it is not carried across.
Scopes currently in use: residential_hpp, provider_general, mixed, unclassified, buy_to_let. A source whose scope has never been assessed cannot be cited by a scoped dataset; the build fails until someone classifies it.
How often figures are rechecked
Figures go stale at different speeds, so they carry different review windows.
| Figure type | Review window |
|---|---|
| Rates and fees | 14 days |
| Availability status | 30 days |
| Eligibility criteria | 60 days |
| Market statistics | 180 days |
The window is the standard; the date is what happened. Nothing on the site yet marks a figure past its window automatically, so the date of the last check sits next to every figure and its age is always visible. The recheck means reading the provider's own pages, and providers can change products between checks, which is why the date sits next to the figure.
How comparisons are ordered
Open providers first, then waiting-list ones, then those we could not verify or confirm, using the availability classes defined in the register section. Within that, by the figure the table is about: the lowest published initial rate on a rates view, the lowest minimum deposit on a deposit view. Ties break alphabetically.
Order is not a recommendation. The lowest initial rate is not necessarily the lowest total cost, and the lowest deposit is not necessarily the best product for you.
Commercial payments never affect ordering, and a build check fails if commercial configuration can reach the code that ranks, matches or prices anything. How the site is funded is on how we make money, including the rule that you never pay us anything.
What the build enforces
27 checks run on every build, and the site does not publish if one fails, with one deliberate exception: a published finding that stops holding is taken off its page and reported, rather than holding up the build. Each exists because a specific mistake reached a page once. 13 of them protect the research itself.
| Check | What it prevents |
|---|---|
check-selection | Commercial configuration cannot reach ranking, matching or pricing. |
check-boundaries | The separations between decision, display, research and engine code hold. |
check-criteria | Eligibility matches conjunctively, so a provider is never shown as a match on a route it does not publish. |
check-pairs | Every rate comparison is one a single real customer could actually choose between. |
check-disputed | A disputed figure cannot be flattened, in either the optimistic or the conservative direction. |
check-ftv-duplication | A disputed figure stays disputed everywhere it is copied, including datasets that mirror it. |
check-product-scope | A dataset about one product cannot be built on another product's sources. |
check-benchmark | External comparisons are vintage-matched and carry every dependency they rest on. |
check-insights | Published findings are re-tested against current data on every build. One that no longer holds stops rendering and is reported for rewriting; one that declares no source stops the build. |
check-conditions | A product's conditions, such as an EPC requirement or purchase only, travel with every page that prices it. |
check-dispute-shape | A disagreement between sources is recorded in fields, not prose, so no page can read one side as settled. |
check-citation-fit | A citation points at a document capable of carrying the claim, not merely at a source that exists. |
check-changelog | Every change-log entry carries a declared kind and a real date, never a future one or one inherited from a site-wide constant. |
The site checks, and how every check is tested
The other 14 protect the site rather than the research, among them internal links, structured data, house voice, layout collisions, and a check that internal editorial notes never reach a published page.
Each is proved by deliberately introducing the error it exists to catch and confirming the build stops. What no check can catch: a build check only sees what has been registered, so it can tell you a source is the wrong product, never that you failed to find the right one.
How software is used, and where it stops
Software holds the records, calculates derived findings and runs every check above. Tables and figures in the copy are generated from the records, so a stale number on one page cannot survive a correction made on another.
Where it stops is evidence. A search result or generated summary is a pointer to a source, never a source. The provider document is opened and read, including scanned ones. More than once a summary attributed a provider's buy-to-let rule to its home purchase plan, and only opening the document caught it.
How a figure reaches this site
-
The provider document
Rate card, criteria guide, register entry: opened and read.
-
Recorded with its date
The source, the date read, and enough wording to check us.
-
Every build check runs
The site does not publish if one fails.
-
Generated onto the page
Tables and figures come from the records, never typed in.
What we do not do
- We do not issue religious rulings. Where scholars differ we report published positions with attribution, and record who certified what. The certification page sets out that boundary in full.
- We do not name a best provider. Suitability depends on circumstances we cannot see, and that judgement belongs to an FCA-authorised adviser.
- We do not give advice. We are not a lender, a broker or an adviser, and nothing here is a personal recommendation.
- We do not publish figures we never verified. If a later check cannot read a figure we published, it stays up with the date we last read it and says so. If the provider's complete page no longer shows it, it comes off the site and the change log says why.
- We do not infer a provider's reasoning. Where a provider publishes an explanation for a criterion we can report it, with attribution. Where it does not, we report the rule and leave the rationale alone rather than inventing a plausible one.
Corrections
When we get something wrong we correct it visibly: the corrected figure on the page, and a dated entry in the change log stating what we said before and what the source actually shows. Corrections are never silently overwritten.
That includes corrections nobody would have noticed: a deposit route inferred from one document's silence, a criterion attributed to the wrong product, a criteria guide we missed behind a different document hub.
Reporting an error. Tell us the page, the figure and what the provider's own document says, at hello@islamicmortgageguide.co.uk. Where you are right, the correction goes in the log with what we said before.
Common questions
- Where does Islamic Mortgage Guide get its figures?
- Provider documents and pages, the FCA Register, Companies House and official statistics such as Bank of England series. Every material figure carries its source and the date we read it. We never use other comparison sites as sources.
- What happens when two sources disagree?
- We publish the disagreement. The figure is marked disputed, every published value is shown, and none is treated as governing until we can establish which does.
- Do providers pay to appear higher in your comparisons?
- No. Open providers come before restricted or unconfirmed ones, then the order is by the figure the table is about, with ties broken alphabetically. A commercial relationship is disclosed and does not change position.
- How do you decide what counts as a material figure?
- Anything you could act on or compare: a rate, a fee, a deposit minimum, an eligibility rule, a provider's regulatory status. Worked examples are labelled as illustrations, because they are arithmetic on assumptions rather than claims about the market.