Thank you both so much for your help - it has been very useful!
I downloaded the turrican soundtrack adf and ran it in FS-UAE / WinUAE, the missing "Base Invader" track is there, it is track "Level 3-2", actually located after "Level 3-3" but before "Level Complete".
I extracted the song files with unadf and they are the same as the Modland files but with different filenames. The "Base Invader" track still does not play with UADE or XMPlay.
There is something wrong with the subsong ordering. There are five subsongs in World 3 according to UADE and XMPlay, but only three are played. In the menu on the turrican soundtrack adf the songs are numbered 0, 1, 3, 4 . 0 is "Level 3-1", 1 is "Level 3-3", 2 does not exist, 3 is "Level 3-2", 4 is "Level Complete". Subsong 3 is the one I need. It seems that UADE and XMPlay skip subsong 3. The textual output from UADE is not very useful. I guess that there is something about the world3 mdat file they don't like. I will try and find a TFMX editor and do some more investigating.