Oh Yes!!! I'm sorted now!!!
After my 2nd e-mail complaint I was called this morning to discuss. Technical support guy said there was nothing he could do, web & walk + web & walk + didn't exist anymore and there was no throttling going on, he suggested it was just too many people using the network at the same time, bla bla bla.
I kept referring back to forums and how others had got their internet sorted out, he kept saying there was nothing he could do, insisting that even if I payed the £5 extra the speed would not change and it was just the way T-Mobile internet worked and 350kb/s was as good as it was going to get.
I told him he was talking nonsense and to Google it and ask his manager. His manager was not there so he said he would look into it and phone me back.
About 30 minutes after the phone call I noticed my internet was off, and has just come back on again. I now have 2mb/s download and .5 mb/s upload which is about 2/3 bars of HSDPA.
Just waiting for them to phone me back to ask if its any better!
Success!