Genghis
You've quoted JAR 22.1(a)(2) but you've ignored the alternative definition in 22.1(a)(3) which states:
'Sailplanes and powered sailplanes the number of occupants of which does not exceed two'
22.1(a)(1), (2) and (3) are ORs not ANDs.
So the Vigilant can fall under JAR-22 and so is a powered sailplane and therefore, I guess, a TMG.
Incidentally, I've not found a definition of a TMG except for the one in JAR-FCL 1.001 which really doesn't help as it refers to them being a sub-set of 'motor gliders' but doesn't define a motor glider! Another conundrum from this definition is that it starts '. . . having a certificate of airworthiness . . .' which of course the Vigilant doesn't.
Any thoughts??