No 3G internet on O2 but have full 3G coverage ?

I'm on O2 in the UK but can't get any internet or email access over 3G, visual voicemail also doesn't work. This is all despite having good signal and the 3G symbol is showing at the top of the phone. If I switch off 3G it connects to the old Edge network and I get internet (although very slow), email and visual voicemail. The consistent message that I get from Safari is "Safari can't open the page requested as the server has stopped responding"

I've already tried the following -

-Network reset, phone reset.
- Tried in different geographical areas in case it was a 3g issue in my Home area.
- Spoke with O2 and all my network settings are correct and they confirmed data is fully enabled for my number. Sim is also OK
- Switched Wi-Fi off (when enabled this works very well at home ...lightning fast)

I also took the phone into the Apple store yesterday and they are convinced it's a network issue. I only got the phone on Wednesday and my number was ported on Friday - interestingly I was getting full 3G internet no problem on the temporary number before this. Since my number has been ported no 3g internet ?

I'm waiting to speak to the data networks team tomorrow at O2, in the meantime if anyone else has had a similar issue resolved it would be great to hear from you.

Love the phone and I'm confident this is a minor glitch !!!!