Dorothy Perkins are currently offering 20% discount on everything - except sale items - this weekend. You can also get a further 20% off by using the code DPCLOSER25 taken from Closer magazine. Altogether this is 20% off! The first 20% is automatically applied at the check out, and simply enter the code upon check out to get the further 20% discount.
Don't forget you can also get cashback! You can receive 5% cashback at Quidco, 10 piggypoints per £1 at Pigsback and 5.05% cashback at Topcashback!