If you go for separates, you can get that Sony STRDE585 for around £200, but that only leaves you with £200 and you can't get any sort of decent set of surround speakers for £200.
This
http://www.richersounds.co.uk/index....hp&p=davs550r2
is more in your price range.
It's probably more worth your while to save up for a while longer and go for the separates.