I'm gonna call this done now. This final stage has added the last final detail touches to the texture, and returned the asset to 3DS Max where all the components have been put back together. Textures reapplied, and appropriate (ART) renderer used to correctly approximate the results I was getting in Substance, and it now all looks good. So here is the final version (weird naked bloke is just in there for scale). Will add the correct wing deployment angles and a few landing configuration shots later.
[EDIT:]
I am just going to add the final renders of this produced in Daz Studio where I'll see how it does on their marketplace. So I had to rig it in there to get the animated functionality I wanted for the end user. Landing and flight config for the wings, working landing gear and associated hatches, and opening canopy. Pretty pleased with the results, Daz3D does have it's quirks, but have managed to get the thing looking pretty much how it did in Substance, which is a bonus.