You might want to look at:
A thinkpad - not as stylish, and the quality has gone down since Lenovo took over from IBM, but they are still near the top as far as build quality goes. Not sure if you can use their own online configurator in the UK, but many places carry them.
Asus - Have a great range, google asus uk and you will easily find ASUS online stores. Quality is right up there, you'd have to research customer support if that is important to you, but they don't have a bad reputation to my knowledge.
Dell - The Sony actually has pretty good specs for the price, but if you aren't bothered about blu-ray then you can configure an inspiron 1520 with things like a bigger screen (1280x900 is dated on 15.4"), better graphics card, the GT over GS which will play modern games quite well, and while Dell may have a bad reputation from some quarters, it has alot better support for laptops than Sony (their downfall in regard to laptops). Search for coupons that work in the UK before buying.
HP - Not sure what UK prices are like but their reputation has shot up for some of their laptop models in the past couple of years.
Check
http://forums.notebookreview.com before you buy anything or for better reccomendations (people will research for your needs). I'd also reccomend a 3 year warranty and accidental coverage if this is a big financial investment for you. more important than getting a slightly faster processor or larger hard drive. If you don't game (3D or processor intensive games) don't bother going for things like 2.2GHz over 2GHz or slightly better graphics cards over others as primary decision breakers.