The transom was in pretty good nick, as I had previously spent a lot of time on it - drilling, drying, epoxy sealing, and filling some 87 unused holes left as a legacy from previous owners, along with a big patch of wet blisters where there had been an original auxillary outboard bracket.
While I had the crane handy, I did take the oportunity to remove the outboard, remove the old plywood mounting plate, and fit a new one in 10mm nylon. Marine Sikaflex was used to bond and seal this new plate in place.