Its possibly an account issue.
I have asked a moderator to provide assistance, they will post an invite on this thread.
They are the only BT employees on this forum, and are based in the UK.
Would this be down to me having the YouView service from BT rather than youview itself?
Not sure how that works, but it should indicate that its available from BT. I am not sure even whether the moderators can advise on it, perhaps it thinks you cannot get a TV signal at your postcode.
I do notice the checker gives you an estimated broadband speed, so that may somehow link back to some database of speeds, and it has no records for your postcode and address.