When we removed the heater box to replace the heater core on Andy's 72, there was a sheet of aluminium that had been pop riveted over some damaged fiberglass. We have cut out that section and let in a new sheet of flat GRP that has been bonded and faired in, once this is painted it will look as good as new.

What a shame it will all be hidden behind a heater box, a heat shield, and some carpet....