Freeview coverage checker

I just used the Freeview coverage checker. It reckons my address is on the Bilsdale transmitter, which is Tyne Tees. But I'm actually in Belmont's area (Yorkshire) and get a lot more than the 21 channels it claims. Why is it reporting the wrong region, and has anyone else got the same problem?

Being in the SW I don't have the luxury of different regions, is Freeview's system the same as the Digital UK one?

http://www.digitaluk.co.uk/coveragechecker/main/trade/tr1+1aa/1/0/NA

It says "Result sourced from Digital UK.", so yes. For some reason that one says Bilsdale too, even though it lists Belmont as an alternate. Shouldn't it expect you to have your aerial pointed to the transmitter with the most channels available?

I suppose it depends if you get your TV off a relay or if the site thinks you get your signal from a relay?

I'm deep in Sutton Coldfield's area but I know there is a transmitter/relay in Brierley Hill so I dug out the postcode for that transmitter (says I could get 80 channels from it as opposed to 94 from Sutton Coldfield despite the fact that BH is almost literally on the doorstep). But a postcode that's literally round the corner from Brierley Hill says Sutton Coldfield is closer (even though it was further westerly than BH).

I'd take the results with a pinch of salt.

For my address it has picked out the worst possible receivable transmitter you could point your aerial to, with the worst signal and the smallest range of channels. It seems not to be a very good tool.

EDIT: The result is the same as Digital UK's. It seems to be based on what future reception will be like and not current reception, though quite why I'd want such a restricted set of channels I don't know

So it's not just me then. They need to sort that out, pronto.