I'd say you've been offerred a pretty good deal there already. I don't know if there's any left now, but when dealers were selling off the last of the ST's over the last few months then they were selling them for £8995, so not much more. I know of someone on the Focus RS forums that ordered a new Focus RS and is getting similar to what you've been offerred for trading in an 08 plate Focus ST3! I know in that case he was silly for not telling them to get stuffed and go elsewhere, but it gives you an idea that you have been given a decent deal there.