Apologies once again for the lack of progress on this one folks, but that's life at the moment I'm afraid. But here's a token nudge forward anyway, just to prove the project is still alive. I wasn't happy with the horribly misaligned trenches on the underside of the engine nacelles, so I disappeared them with a mix of CA and talc:

There's still a faint trace of them here and there, but I can live with that. It certainly looks much better than before!
I also managed to reshape the intake section of each nacelle to more closely match that section on the resin cowlings:

The final result will depend a great deal on the job I do when attaching the engine parts to their respective cowlings.
Here's a couple of photos of the finished bulkheads I added:


Still got a problematic seam, though:

Once I've attached the resin cowlings, I'm in for several more rounds of filling and sanding!
Kev