I have written about Quidco before but they have just started offering a rebate – a rather small one to be fair – on all BA flights. It had been restricted to Club Europe flights in the past.
Typically it won’t come off the taxes or fuel surcharges, but every penny helps. Remember Quidco charges £5 per annum membership which they deduct once you have earned £5.
(Link above does not earn a referral payment for me)