Have been with 3 since August 2010, 2 year contract came with a HTC Wildfire and everything was fine.
Recently lost my phone+sim while in the US, but I had bought myself a Motorola Droid 2 Global to use on a US T-mobile PAYG sim while I was there. Sucks that I lost my phone, but at least I could get a replacement sim to put in this one..

Get back to the UK, get my replacement sim, stick it in my phone. Phone comes on, connects to 3 UK - no 3G connectivity and no calls/text, new sim comes with a letter that says please allow 48 hours for activation. Cool!
It has been 6 days now and still I cannot make calls or send texts and there is no 3G connectivity. Customer services were really not helpful, saying 'You need a 3G enabled phone' and not having an answer when I told them I had a 3G enabled phone, but they assured me that the simcard was activated.

I have since read some stuff about 3 simcards using a strange network connection or something, incredibly technical stuff that is somewhat beyond me. And so this leads me here and to this question~

Does any fancy network boffin know of any way to configure my Droid 2 Global to work on the 3 UK network? I am completely comfortable with flashing firmware and such, I already had to do quite a lot of fun things to get it working in the US to connect to T-mobile*!

On a side note, I was happy with 3 until I contacted their customer services.. really horrible experience, I wont say how many phone calls and emails there were, but out of them only one person I spoke to was actually helpful and explained some stuff to me - sadly I couldn't get in contact with this person again.
Even if I can get this phone working on 3 I am not sure I will be renewing my contract come August.. I definitely noted my displeasure to them.

Well, that is all for now. If anyone can lend any help at all (all my googling produces really only one result that is someone asking the same question as me and not getting an answer) it would be greatly appreciated!
Thanks in advance~

(*Something about Verizon asking Motorola to stop the receiver from actually working on some GSM/UMTS bandwidths so that people couldn't use T-mobile or AT&T networks and were stuck with Verizon, cheeky sods)

Last minute: Aha, tomorrow my sister is coming back from Uni, she has a HTC Wildfire (originally from O2, I believe) that I am going to try my 3 sim in.