Thanks for that Zirk, I'll stick with what I have until 3 kick me out and then I'll go elsewhere.
Although I'm eligible for a free upgrade from the end of April, my 24 month contract dosn't finish until the end of June. That's when I'll expect 3 to get in touch terminating my unlimited data allowance! Forwarned is forarmed! 
Thanks!

Glad it was informative, let us know how you get on.

Strangely enough I had a call a few days back from EE as I have a second Sim on T mobile Full Monty (ie, full everything) which tends to get hammered on Data when Im out and about, Ive had the Sim Contract for 3 years now as I originally got 50% discount bringing down to £14 pm and they've always renewed the same deal for me every 12 months, on the basis I dont leave.
Anyway my contract is up mid April, so the Upgrade Team from EE are telling me 'we not playing that game anymore, your have to sign up for an EE 4G Plan as from Jan 15 were not not selling or upgrading Orange or T Mobile plans anymore as were closing down the Networks this year'. My response was unless your prepared to offer me some kind of decent Data Package, it probably wont happen as I tend to use my Voda Full Red Plan for mins and txts which they almost give away to me. Needless to say, they couldn't offer me anything like to Unlimited Data thats part of the Full Monty Pack on an EE 4G Tariff, let alone the price, so with that I politely said I'd think about it and ended the call.
I then thought I would try it on and called the 'If you are thinking of leaving us team' (Retention), and asked for my PUK Code and to give 30 days notice to quit, when asked what the problem was, and I explained, the outcome is Im now on another 12 months on the Full Monty Plan and the same 50% price deal.
Guy did say though, 'I wouldn't count on this happening again next year though'.