Thanks Greg, it seems you've solved the major mysteries, especially regarding how Mobilco got access to a rather advanced imported machine that no-one had ever heard of. Did your second machine also have the ILO 2-stroke originally, or did they also use some other engine? A 9.5 hp 2 stroke would use fuel in sufficient quantities to require frequent in-flight refuelling.
The 1965 manufacturing date is earlier than I would have guessed. It makes the Emperor even more of an oddity, and therefore collector's piece. It also would explain the seemingly bizarre choice of Whitworth bolt-heads: it would have been unusual, but not impossible, at that time. (Alroh were using them in the early 1960s, too.)
