ScottC is spot on... Did you also get a chance to generate the security key (random mouse movement)...

Things are a little more managable with the corporate server (BES) vs the non-BES, so any possibility of things may be "mis-set", if the device can log into the Blackberry service (via the blackberry.net APN) then it will go to "GPRS". Once this happens, setting up the device for mail will be easier.

Can Blackberry UK give you a link to re-download the firmware they support for the device. This will normally have the initial service book link to pick up the T-Mobile UK one...