That is my point - there are several sets in service where one first class section HAS been de-classified (i.e. headrest covers removed, window stickers removed, litter bins removed, internal doors locked out of use and external large '1' between the windows removed), but which STILL retain the external yellow stripe. Given that the yellow stripe has only to be covered by a dark stripe of the same dimensions, it wouldn't seem to be too hard to do this at the same time!
As a daily user of the North Downs line I know that FGW's performance on the route is dire (information wrong, trains late and frequently turned short, stock ill-maintained, etc.), so all 'digs' are entirely justified.