Thanks guys. funnily enough i spokr to London Camera Exchange yesterday and they also reccomended the Sigma 17-70mm. Think thant sounds like my best option. I'll leave the 70-200mm for a while and play with the 1 lens and maybe borrow a few longer lenses if i can to see what i like.
On the UV filter I was quoted £70 for a 82mm Hoya Pro1 digital UV filter (to fit the sigma 24-70 I was looking at). The prices on Amazon are MUCH better. Thanks again,
Right now to find the best deal on that combo. wish me luck and I'll get back with some results once I've got my self sorted.