I can't remember what size frame you're after, but a quick ebay search narrowed down to 54cm frames brings back 53 results. Straight away this one in Leeds ends in just over 6 hours and looks a decent bike but will push your budget,
http://www.ebay.co.uk/itm/Pinarello...0950219296?pt=UK_Bikes_GL&hash=item3cc1d85a20
This could be worth watching to, ends on Wednesday night at 22:10. Pick up only, buy any seller worth their salt will package it and you can arrange a reverse collection with APC Overnight for approx £25-£30.
http://www.ebay.co.uk/itm/Specializ...0667116543?pt=UK_Bikes_GL&hash=item43ad1c37ff
Then there's this one, not pretty but could be very cheap,
http://www.ebay.co.uk/itm/claud-but...0847142835?pt=UK_Bikes_GL&hash=item4ab3fadfb3
[EDIT] I'd seriously watch that Specialized, it's a very well specced bike, and presuming everything works as it should it's pretty much future proofed as far as upgrades are concerned.
Thanks for the links.
I've been keeping an eye on a few Specialized auctions, but the ones going for circa £300 are usually 2006 models. Don't think I want to spend money on something 6 years old.