If I attempt to stream media (iplayer) on my iPhone, I get a message saying this the service is only available to '3' and Vodafone contract customers, except users of Android and Apple devices. Therefore I should be able to stream.
T-Mobile tell me that I should indeed be able to access the iplayer via 3G.

Has anyone else had this issue and resolved it?

well itrs true that its limited to 3 & vodaphone, however i use skyfire on my nokia, t opens web pges as if it were on a real pc, so it trick ilayer into thinkingim uing a home cmputer and not a mobile. try that http://www.skyfire.com/