Thanks guys. I've seen a suggestion that maybe the BT Openzone and T-Mobile landing pages cause problems for the 770 web browser. So is there anyone who has been able to access these services specifically? Or maybe with a Nokia 800?

It might be that once one of these Mozilla projects has been ported to the 770 that I can use these hotspots, but unless they get ported soon then I think I may have to return my 770 now and check out the situation again in a few months. Ideally the WiFi providers should fix any incompatibilities they have but practically unless/until they do my 770 will be of little use.