I would whole-heartedly recommend Acer laptops and/or netbooks. The build quality might not be as great as those of other manufacture but they definitely give "bang for the buck". (Or Pound in your case!)
The Mrs. and I have an Acer Aspire something-or-other with a 17" LCD screen and Dolby digital speakers. We bought it a couple of years ago for about $500.
My kids all have Acer netbooks, courtesy of Dad and his Mrs.
They really enjoy using them.
Acer. Highly recommended. (And, no, I don't work for Acer nor do I have anything to do with them. Just a very happy customer.)