Zoostorm have been about for some time.
I've got severe doubts that you will get a laptop at that price to play those games well. I have a quick look at Bioshock for example and the laptops you are looking at meet the MINIMUM specs.
Laptops are not really great for games and for £800 I don't think you will get a laptop to run it well. It may well run them but I would think you have to drop all the settings. The problem with them all is the graphics. I could be wrong but I think you're hoping for too much.
I'm ready to be corrected by anyone that knows better.