Mate i get 450 miles out the tank so not thrashing anywhere lol the brakes were taken apart few weeks ago down to a ticking noise when on left lock which has now gone, not sure if that has anything to do with it.
might be handrake sticking on sometimes when you drive your car a few miles get out see if one wheels hotter that the rest if so something is binding on ie pads or rear handbrake shoes does your car pull to one side when braking ?
dont kwik fit do a free brake check? might be worth going if even just for peace of mind
my 2p says maybe some oil off your hands was transferred to the friction material when you stripped the brakes last time...maybe lol.