Thanks for the info.
I'm sick of being fobbed off by T-mobile. I've just been speaking to their "technical support" team, there's a contradiction in terms, and they said that it's a problem with the hardware and I should take it up with HTC, but in the same conversation I'm told by the monkey that his colleague sat next to him has a G2 and has no problems at all in sending MMS.
Their proposed resolution is to offer me a non like for like replacement such as the G1! Duh!!!
Is anyone else on T-mobile but not have this problem?