My first Morgan, a 1985 cvh 4 seater and therefore before the frames were dipped (I think), had previously failed an MOT on a number of things including woodworm.
Our first house had a woodworm infestation and the mortgage company insisted on professional treatment which carried a 30 year warranty. When I called them back the following year because beetles emerged, they said that it was 'post treatment emergence' and that it didn't require further treatment because the emerging beetles would be sterile. No internet then to research their claim but I've sometimes wondered whether it was just to avoid the warranty....