Asbestos survey cost London: Asbestos Survey Price Index

Every row is a verbatim sentence read from the named source's own page through our fetch service on the date shown, hash-pinned to the stored read (the sha of the page's visible text; the raw page is mirrored to R2).

19 of the 43 named sources that could be read published a usable figure; 24 published none and are recorded as not published, never filled in; 6 could not be read (blocked, dead or unreachable) and count nowhere.

The headline figures (median, minimum, maximum, quartiles) are over ONE figure per source for each breakdown it prices, in GBP (a source's median where its page yielded several accepted sentences for one breakdown), so a page that gives figures for several breakdowns gives one for each and N counts 28 figures, never sentences; 227 candidate sentence(s) were refused by a reviewer with the reason recorded.

The fuller derivation this dataset is chartered to grow into (not yet what the figures above are; they are each source's own published figure as read): Nobody publishes a GB asbestos survey price series, and the one number a buyer wants - is this quote normal for my property, in my city - cannot be read off any single surveyor's page.

Ours is the aggregation: the median, minimum and maximum advertised price per survey type (management, refurbishment/demolition, sampling-only) and per property class (flat, 2-3 bed house, larger house, commercial per day), computed across every surveyor that publishes one; the count and SHARE of surveyors publishing a price at all against those that quote only on request; the London premium measured as the difference between the London pages and the same firms' national pages rather than asserted; the per-sample laboratory rate as its own row because it is the line that makes two quotes incomparable; and repriced-since the previous read.

Every figure is quoted verbatim from the surveyor's own page with the retrieval date; no range is interpolated and a firm that publishes nothing is recorded not-published, which is itself one of the index's figures.

227 candidate sentences on these pages were refused by a reviewer; each refusal and its reason is recorded in the review ledger.