Instructions:If you're around London, Birmingham or Manchester this weekend, get 20% off your purchases at Selfridges from Friday to Sunday. Print off the voucher which can be accessed by clicking the link and present it at the till when you pay. It can be used as many times as you like.
There is a hideously complicated list of exclusions, which can be accessed here (cut and paste URL), needs Adobe Acrobat. Prepare to get a headache.
Still, might be useful to someone!