They'd probably got some people in from the Araldite mafia on the Clyde - who have form for this sort of thing.
Swan Hunters on the Tyne were also practitioners of this technique as well. It was found on a major warship now scrapped, that the Geordies had employed someone to guillotine the heads off screws, so they could be glued on. It would likely have saved more time and effort just drilling the pilot holes in the first place.