TMG = Touring Motor Glider
SEP Class = Single Engine Piston generic rating.
Type = Something which has a Type Rating, not a generic Class Rating.
Variant = different breed / model of SEP Class aeroplane. Thus a C152 and PA28 are different SEP Class variants - if the pilot has only flown a C152 and now wants to fly a PA28, it is a legal requirement to receive familiarisation on the PA28. If it's a PA28 with a VP prop, the pilot needs to receive 'differences training' if he/she hasn't flown a VP prop aeroplane before - and that has to be with an instructor.
After a fatal accident in the UK many years ago, the CAA came up with 'strong recommendation' that an instructor should not conduct instruction on a variant he/she hadn't flown before, until such time as he/she had received variant familiarisation - if I recall correctly this was an accident in a Cherokee and the pilot had only flown Warriors previously. One used KIAS, the other mph....
I had about 8000 hrs TT when I asked another FI to give me a quick 'familiarisation' trip in a Cherokee 180 as I'd only flown 140s and Warriors before then. I'm glad I did as there were several clear differences - as a student with whom I was flying one day also discovered when he pulled out the plunger type mixture control instead of the carb heat...with the predictable result (briefly!). All our other aircraft used quadrant-type mixture controls...
