That did the trick. Excellent, thanks. However, playing around in the dark has revealed another problem, my lovely metal textures turn transparent when I switch the lights on! :-(
OK, I did that and it has prevented my metal textures from going transparent. Now they glow in the dark, slightly, when I put the landing lights on. Not really noticeable on the engine cowlings as these would be bathed in the lights anyway, but the nosecone (this is an airship BTW) glows too and this looks silly. :-) With just the navigation lights it's fine. Is this something I'm going to have to live with?
Ah, turns out that it's black for FS2002 as well and my black wasn't black enough! Now, if that doesn't mean you accidentally transposed FS2002 and FS9 and it really is black for both then I'm ready to upload as soon as a m8 has flight tested in FS9.