The old UK CAA PPL's came with a SLMG rating attached. To get a TMG rating you had to "unfreeze" the SLMG rating by having a checkout in something like a Falke or Grob, send off the proof + £70 and you'd have TMG rating. You could then fly either SEP or TMG and cross credit the hours to keep both ratings current.
Touring Motor Gliders have fixed engines rather than "pop up" ones but can be flown on an SLMG or TMG rating.
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