Update:
Gamersgate have put the pages back up, but the .uk prices have been increased. The prices on the .com site are the same as last night (and are slightly more expensive than the UK prices were), but still cheaper than Steam and Amazon.
Standard: http://www.gamersgate.com/DD-F12013/f1-2013
Classic: http://www.gamersgate.com/DD-F12013CE/f1-2013-classic-editio…
Original deal:
Better than Amazon's current price of 16.99/22.09 USD and Steam's current price of 23.79/30.59 USD.
Given Gamersgate's track record, and the fact that both Steam and Amazon are only doing 66% off (it's currently the Steam daily deal, so that's as low as Steam will go during this sale), it could just be a pricing error.
Standard: http://www.gamersgate.co.uk/DD-F12013/f1-2013 £4.80
Classic: http://www.gamersgate.co.uk/DD-F12013CE/f1-2013-classic-edit… £6.40
The game activates on Steam.
Edit: Pages have been pulled, typical pricing error from Gamersgate! For anyone who did get in, enjoy!
Damn, doesn't seem to be available anymore.