In terms of what to buy and where to buy it, well some suggestions.
Go for a "name" make. Places like PC World, Currys etc do "no name" laptops that do have a poor quality reputation. Dont let the staff talk you into buying one of them.
Go for Toshiba, HP, Compaq, Sony, Dell, Fujitsu Siemens, that sort of brand.
Avoid Advent and Packard Bell (which may be PC World only I think) .
Plenty of places now sell laptops online, some you may not normally consider.
Look at Dell, Argos, Tesco, Woolworth, Staples, Asda and so on.
Be careful of "fake" reductions from places like PC World, Currys. Some of these companies have specific laptops they hold back till after Xmas so they can be in the sale. They may look as though they are reduced but probably aren't.
I have a Staples shop near me and they seem to have good deals on PCs, laptops etc.
Hard to give advice on specific models till we see what is in the sales after Xmas.
No doubt we will get bombarded with adverts for laptops from Boxing day onwards.
This is a good site for finding deals (on everything not just laptops)
http://www.hotukdeals.com/