Thanks Guys, I'm making it up a go along so I'm very open to suggestions.
I think I'll;
Glass the whole body as one piece.
Mark it up and cut it into the different sections, slitting saw on the shell and Hotwire the foam.
Lap and tidy up the joints.
Fit it all together and finish the outside.
Take it apart and make molds of the separate body pieces.
Carve most of the foam out, some foam areas will be left in and sandwiched over to strengthen them, e.g. around the tail extension insert.
This is all subject to change as I teach myself stuff, I've watched a few DVDs on building plane bodies and going to try and follow that.
This bodyshape is likely my only go at this, I'd like to give it a good go at making it decent.
jon