Neil, the Caonon outlet on ebay, as above, is ace - you'll get the best deal going. Don' buy a 400d from a high street shop.
Don't take any notice of the 'refurbished' note on the auction - this is just to keep Canon's hight street dealers happy - your camera will be brand new.
If it was me I'd buy...
http://cgi.ebay.co.uk/Canon-Digital-...QQcmdZViewItem
or.....
http://cgi.ebay.co.uk/Canon-Outlet-D...QQcmdZViewItem
and save enough money to buy.......
http://cgi.ebay.co.uk/Brand-New-CANO...QQcmdZViewItem
The 18-55 lense is OK, for what it is, but the 17-85 IS USM is so much better.
Before you buy a Canon though talk to Jimmy about Nikon's - he loves them.