Having seen this thread I did a bit of research and found that Ryobi do an impact rench as part of their one+ range and as I already have a drial that came with 2 18v batteries I may get one through work, I maybe able to get it at a discount
Talking of Halfords, they do a range of tools called Halfords Pro, apparently these are made by Snap -On, Tang and Mac to their own standards, Halfords gurantee them for life. Every year or so they change the design of the socket sets so they flog off the old designs cheap like up to 70% off, last year I got 1/4, 3/8 and 1/2 inch socket sets all for around £100, I've also got a set of ratchet spanners and a very good screwdriver bit set based around a rachet spanner.