What a £4–£7 automated postcode check gives you, and what a full pre-purchase report adds

What £5 buys

The cheap checkers all work the same way, because they all draw on the same open data. A postcode goes in; the service looks up the point against the Environment Agency's flood maps, the British Geological Survey's ground-hazard grids, the UKHSA radon map, the Mining Remediation Authority's coalfield layers, the EPC register, HM Land Registry's Price Paid file and police.uk's street-level crime; and the labels come back. Some add a flag for a company-owned title from the Land Registry's corporate-ownership datasets. The result arrives in minutes, on screen or as a short PDF, and the price reflects the fact that nobody had to do anything.

That is genuinely useful. If you are comparing six properties on a Sunday evening, a quick set of labels for each tells you which two to look at properly. Our own free tools (the flood check, the subsidence checker, the EPC checker and the street check) do the same job for nothing, with the source and the resolution printed under every number.

Where the cheap checks stop

The problems start when the labels are treated as answers. Four things a postcode-point lookup cannot do on its own, whatever it costs:

• Resolution. A flood zone is drawn for a point, a ground rating for a 65 km² cell, an EPC for one certificate that may not be the current one. A label without its resolution reads as a statement about the house. It is not.
• Gaps. Registers fail, time out and have holes. A check that returned nothing is a gap, not a pass, and many automated outputs cannot tell you which of the two you are looking at.
• Interpretation. "Significant" for shrink-swell clay means something different a hundred metres from a Low cell than it does in the middle of the London Clay. A label does not carry that.
• What to do next. The point of a pre-purchase check is the question it puts to the surveyor, the seller or the conveyancer. Labels do not write questions.

What the full report does differently

The Complete report is one document of 33 numbered sections for one address, in this order: HouseCheckup IQ Score, What stands out, Flood risk, Flood defences nearby, Ground & subsidence, Ground hazards across this area, Contaminated land, landfill & environmental permits, Air quality, Price history, Rental yield, Council tax, Tenure & leasehold, Property facts, Energy & running costs (EPC), Solar potential, Broadband & mobile, Heritage & what you can change, Planning & land designations, About this area, Amenities & walkability, Crime, Schools & Ofsted, Getting around, Noise, Checked by hand for this address, Neighbourhood deprivation, Who lives here, Food hygiene nearby, How we scored it, Corporate ownership and building records, Questions for your surveyor, Before you offer, Sources consulted. Each section prints where the address has usable data, and a check that could not be run is named rather than scored as a pass. Lite prints the hazard-screening sections (Flood risk, Flood defences nearby, Ground & subsidence, Ground hazards across this area, Contaminated land, landfill & environmental permits, Air quality, Before you offer, Sources consulted) and lists by name the Complete-only sections it does not include, so a Lite buyer knows exactly what was not run.

Two things sit under every section. Every reading carries its resolution (the postcode point, the grid cell, the certificate date), so nothing reads as a claim about the building. And every section states its resolution and names what was not found, so a blank is never read as a pass. For the full list, section by section, see Lite vs Complete.

When the cheap check is the right call

Honestly: more often than a company that sells reports would like. If you want to rank areas, a cheap check or a free tool is the right tool. If you are a landlord screening twenty flats, the per-property price matters more than depth. If you only need one fact (is it on the coalfield, is it in Flood Zone 3?), the official register answers it free. The report earns its price at one moment: when you have found the property you intend to offer on and the cost of a missed finding is measured in thousands, not pounds.

What none of them do

No pre-purchase report at any price inspects the building, values it, names its owner or stands in for the conveyancing searches. A RICS survey inspects the fabric. The local-authority, drainage and environmental searches are legal documents your conveyancer orders. HM Land Registry's title register is the only source that names the registered owner. Every report, cheap or not, is desk research from public records, and the honest ones say so on the first page.