Stuck the folks on giffgaff, but they're on one of the cheap deals - the perk being that as well as getting stacks for their money inc free texts and calls to their favourite son, whenever anyone rings them - their call allowance increases a minute, for each minute they're on the phone.

Anyway - plumped for the Lumia (can't remember model number) over the Xperia and a Samsung Windows Phone.
Found a good sim free deal on Amazon, so will be playing with that over the weekend hopefully (depending on when my new GiffGaff micro sim turns up)!