Managed to do a trial fit of the main body shell today.
Body 001.jpg
Cockpit seems to be in the right position against the front and rear parts of the frame.
Body 003.jpg
But the offside front of the shell seems to be sitting a bit high.
Body 007.jpg
The web on the left hand side of the photo below is supporting the body and so I will take some height of this web with the angle grider. It is difficult to see on this photo but this fibreglass lip is about 1" above the bulkhead and there is a large 2" gap behind it.
Body 008.jpg
The lip in the middle of the shell (ie where the heater used to be) is flush against both the horizontal and vertical faces of the bulkhead.
Body 005.jpg
Chris