Job done, unit tested, all clean and lovely, old unit disposed of, genuine charm and amusing banter.
Took him just over an hour, first getting the oven away and clear, then finding the fixings of the old one, but because HE'D DONE IT BEFORE NUMEROUS TIMES, he knew where to look and had the right kit. Out with the old hob, prep'd the work surface and fitted the new, TESTED WITH LECCY THING THAT I DON'T HAVE, and cleaned up.
A handshake and forty notes.