If you are getting a discounted bike (by that I mean a 2010 bike that is now on sale) through C2W then check with the retailer if they add on an extra charge. The online retailers I have looked at that go through cyclescheme add on 10% to sale bikes.
I tried a Giant Defy 2 last year and filled out all the paperwork only to run into some admin problems at work so I'm still on the look out for one or possibly a Giant Defy Alliance (£770 at tredz)
Good call. I'll be sure to watch out for that.
Thanks