For anyone interested, the outcome is as follows.
Booked a Genius appointment, got there and some guy asked me what the problem was. I explained to which he said yes they can replace it, but there is a charge. He asked me how much I'd been told, I said 140 and he said they've just recently reduced the cost to 120 quid.
Went to the station when called, explained again. She got all the phone details up, saw that it was 10 days old and she said she would see wot she could do. Came back and as a one off, they could replace the phone at no cost, but my details would be took and any further claims or problems etc that the Apple warranty doesn't cover then I would be charged.
All in all I'm pretty happy. I got extremely lucky but you've got to take your hats off to Apple for doing that for me.