UK? That's gonna be tough. I did a comparison between Dell XPS15 (US), Vaio F-series (US) and what you get from Dell-Vaio UK. Turns out the US models had better hardware and were cheaper by about £200.
Anyway to answer your question, I found these:
£705 Asus P52 which has 15.6" screen, Core i5-460M (2.53GHz) and Nvidia GeForce 310M (1GB) GPU.
£700 HP dv7 which comes with 17.3" screen, AMD Phenom™ II X4 (1.6GHz) and ATI HD 5650 (1GB)
£700 HP dv6 which comes with 15.6" screen, Core i5-460M (2.8GHz) and ATI HD 5470 (512MB)
And for fun, you could go to Dell's and Vaio's websites and configure a laptop.