British Airways launched on Quidco and TopCashback last June, but pulled their offerings a few weeks ago. You can still earn cashback on ‘flight and hotel’ or ‘flight and car’ bookings, but not on stand-alone flights.
BA has now returned to Quidco, though. You can currently earn £7.50 for every long-haul flight booked on British Airways via Quidco.
This is not a bad deal, and it may even be more generous (at least in Economy) than the old cashback scheme which paid a fixed percentage.
TopCashback is not offering anything on BA flights, so it is unlikely that they would match this under their cash match promise.
What is not clear is whether it is £7.50 per booking or per person. I assume it is ‘per booking’. This creates a dilemma for a couple who do not have British Airways status, as two separate bookings (doubling the cashback) would mean that you would be seated apart. That said, it is likely that two adjacent seats would be available when check-in opens.