If you don't get an answer on here (but I expect you will) contact your local Citizens Advice Bureau, they have this sort of info to hand.
Not sure how it works for you for future planning though, are you giving up a works pension? Not sure how stopping work might affect state pension contributions too. There is probably a maximum amount you can be paid - I don't know but I wouldn't think that you get your pay made up to cover your existing salary (depending, of course, how much you earn at the moment).