Finally. Got main deck fitted and glued down - via extending the bulkhead slots.
It wss still very 'sticky' to persuade the deck to move into place. That seemed mainly; the bulkheads/ribs are locked in place by 5mm lower deck but need manipulation to allow the main deck to slide down. Hind sight for me but I would suggest to anyone coming behind, ignore instructions to glue the bulkheads to keel & lower deck until you have gotten the main deck in place - then have the fun of gluing everything in limited space!!
Also I found that the main deck very easily bent around the shallow camber beams so maybe splitting the main deck into two longitudinally could work...
the main deck is 0.8mm 3-ply and I'm sure it has been compressed under an old fashioned steam roller, or maybe Terminated under a large hydraulic press - I found it very hard to cut!!
I have the foredeckportion planked. Wondering why, a bulkhead gets placed behind the planking, another deck above and ship planking around the sides, so it will be interesting to see how this deck planking will be seen!
suey attached the following image(s):