Just been looking online and Additions direct have Wii fits reduced to £69 from £79 and currently (today only!) have £30 off voucher when you spend £60 (ZQ270), so you could get this for the bargain price of £39! You need to do this order over the phone to use the voucher - 08448220099
They are currently offering free next day delivery too!
Note - it says they are 'instock' and stock level shows as green, but then says 'Delivered within 10 weeks' So i'm not too sure whether they are in or not!