Most gliding clubs can put you in touch with a SLMG instructor so you can get your SLMG rating and then fly motor gliders. Finding a TMG examiner though is far more difficult. The aircraft you will be able to fly are the same, but unless the bit of paper says TMG the hours can't be credited towards revalidation of your SEP. I have a TMG rating that has expired and need to find a TMG examiner to renew it.
SS