£123.50 on CRC bought as a pair with Quidco cashback.
Merlin do a bundle with front and rear mechs, if you have a use for those it's £183.82 through Quidco. If you can get more than £60 selling the new mechs on then you'll saving a bit more.
Merlin are doing a 50% off deal at the moment...hurry! http://www.merlincycles.com/bike-shop/r ... 6_673167_8