Cut heat inlet and exhaust pipe holes in bottom cowling

This was an iterative process. The first step was to get the previously-fitted cowling clamped into position, along with the muffler with the tail-pipe removed and cabin heat inlet tube not mounted. Marks were then made in the approximate locations appropriate for the tail-pipe and cabin heat inlet tube. Holes of intermediate size (30mm) were opened up and the alignment and final needed size reviewed