Thanks to all for the comments, much appreciated!
The mock-up engine was a little too short so I added a spacer under it to bring it up a little, then refitted the nose and added the exhaust. It does show if a light is shone at the front so it's been worth the time spent doing it. The cowlings are now on and just need a little more sanding to fix the fit issues.

I have added "hinges" to the lower wing mounts, and the bar at the rear of the fuselage that locked the wings in the folded position. A dry fit shows that the bar matches exactly to the rear strut location of the folded wing, which is a good thing as that is what it locks onto!

I've also been working on the floats and upper wings. I drilled out the float mount holes to take 2mm rod, glued that in place and added several layers of Mr Dissolved Putty to blend it all in. It will be sanded to the correct shape when it's good and hard, and the rod will be drilled to take the float spacer bars.

The upper wings were separated from the centre section, which was then in 2 pieces, so they were joined and filled. The cutouts at the rear were removed to allow for the wings to be positioned folded. So far it all matches up nicely and I should be able to add the "hinges" on the top wing very soon. The plan is to assemble and rig the wings separately then attach them as completed items to the centre section/fuselage assembly..... we'll see how that works later......

Thanks for looking in!
Ian