Evening All
Thanks to you all for the very kind comments: I really appreciate the support that you give especially at times when my mojo is a bit lacking or I am working on an awkward element.
Frank: I think that I may have used slightly too large brass bar for the fuselage structure, with the result that it does have the strength of an old Matchbox car! I had not allowed for the increase in strength of the thinner bar when it is soldered into a structure like the above: I was concerned about the longerons bending. However I can live with it and I am sure that when it is painted it will not look too overscale in thickness.
Ian: you are 100% right - it would have been easier to complete the fuselage structure without the wings, but then why make something easy when with a little (lack of) thought and planning, I can make it more difficult for myself?!
I intend to represent one half of each wing as if it were covered in fabric and the other half to show the structure: the lower wing will be covered on the port (left) side and uncovered on the starboard (right) and the reverse will apply to the upper wing. Hopefully that will distribute the weight of the model more evenly. I have already shown some wing blanks as prepared from the moulds, but here are a pair of blanks after they have been removed from the plastic sheet and are ready to be assembled:

They are for the upper wing as they represent the starboard side, but the lower port wing half is very similar. I started assembly of the port wing by drilling holes for the struts and rigging wires in the top face. Thread was passed through the rigging holes and secured with small squares of scrap plastic. The spars were CAed to the top wing surface and the edges of the wing packed as necessary with scrap strip and card. The latter made a better joint surface between the upper and lower wing sections and helped fill gaps caused by trying to marry two moulds together. Experience gained using this method of construction has taught me that filler will be needed in these areas:

After the two wing moulds had been joined, using copious amounts of tube and liquid glue, and this had been left overnight to harden, I applied large quantities of filler:

At this stage the whole structure looks a mess - indeed it was a mess, but patient filing and sanding, and more filling and sanding eventually resulted in a wing surface which when painted will be quite acceptable:

The upper surface ribs were applied by using 10 x 20 thou Evergreen strip which was allowed to dry thoroughly and the sanded to thin it. Mr Surfacer 500 was applied first to the edges of the strips, followed by 1000 grade to eliminate any small undulations and provide a smooth surface for priming.

The plastic bag which conceals the fuselage and spars of the starboard part of the lower wing is not there to hide mistakes or horrors of the model: it is there because later I will have to paint the new wing. Following the painting I will have much work to do on and in the fuselage, including painting the fuselage frame, and on the exposed wing structure, and I wish to be able to protect the newly painted wing.
Next I will make both sides of the upper wing before I proceed any further with the existing structure.
Thanks for looking.
Stephen.