my personal experience of importing a laptop into the UK is that, unless you can bring it into the country personally, and you get a REALLY good deal, then not to bother.
why?
firstly, if you have it shipped, Customs WILL charge you for it, and they'll charge as much as they can, possibly more than they actually should (they have the power to invalidate the declared value on the CN22).
Secondly, if you bring it in yourself, you still have three problems:
1: The manufacturers warranty will almost certainly be invalid
2: The keyboard (might) not be a UK version which will be incredibly annoying at some point
3: sometimes, manufacturers have different chassis configurations for different regions (i'm looking at you, HP and toshiba!) and in that case, spares will be... difficult to acquire.