Right, I think that I have finally understood the way the wing leading edge assembles. I think that the leading edge centre strip is made from 2 parts, a 3/8" X 1/8" spruce strip and a 1/8" balsa filling strip. These are glued together then glued into the front fuselage assembly and it is this assembly that is slide onto the assembles foam and spar leading edge main part. It is too late for this first one I am building but I will probably do a second one once the first is finished.
I have also, finished the stab ready to add the hinges. made the fin, and am well on with the rear fuselage. I can see how, once organised, Clayton could make them in quantity. I would guess that one could be finished every couple of days.
I will need to update my templates once I get this one finished but I will post the final set once I am done.