Thanks mate! I suspect it will get grungier as things go on, but keeping the pointy bit :)
I put some primer on the hull to get a look at it. It appears I have a clean (ish) hull to work on. There are some pits in the outer edges which need filling with something a bit softer than CA, but they aren't really visible from this angle.

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The seam on the bottom is clearly not in line, I'll probably have to slice a bit off at the stern and make sure the outer skin pieces do line up and cover the mistake.

I also bought some more junk for possible engine parts - a hose coupler, some Japanese novelty sausage extruders, and the back bit of a suction cup hook.

I was thinking about two engines, but that's a terrible design - if either one fails I don't think the ship can fly. There'd be no way (assuming that the main engines are a lot more powerful than the maneuvering system) to thrust without spinning. If there were three engines you could have one fail and always get thrust through the CoG.
I some glue tests and got seriously fed up with things that didn't stick to other things. The best parts are the pipe coupler rings which appear to be ABS. I tried using a slice of ping-pong ball as an insert to make the engine bell, and it looked great but I don't like the idea that it's made of celluloid, so removed it again. Instead I used an internet tool for metalworkers to lay out a frustum touching the ID of the ring at the back and again at the narrow point. I extended this a bit further since I found a nice piece for the "flame holder" or whatever spacey equivalent it is:

The frustum (truncated cone, fact fans) insert is from 0.5mm styrene sheet, cut with a compass cutter and formed around a wooden spoon handle with boiling water. I didn't brace the back of the cone join except for the narrow end, since it would have fouled the ring. I think it would have been a lot easier to brace it and trim or file away the bracing where it touches the ring, since I had to do a fair bit of filling and sanding to remove a dip and seam where the edges wanted to pull apart.
Given the sanding, I thought I'd better fit some ribs to disguise the smoothness (or not!) of the inside.

The mounting is a 1/72 AFV part (AS-90 casemate IIRC.) I might raise the bell up a little bit with some tubes and such, not sure yet.
Cheers,
Will