Wallace,
My firm put me up for the Trainer/Examiner position. You can only hold an examiner authority for individual firms but the trainer rating (TRI) is your own and can be used anywhere. The sponsoring firm have to nominate you to the CAA for the TRE. As with everything in this business this whole process costs a fortune.
Before you can take a TRI course you have to do a Core course of instructional skills, then you can take the TRI and finally the TRE. This all costs about £17000 plus extras(sim time, accomodation....).
On top of these costs are the inevitable CAA fees, for example £1156 for the attendence for one day of a CAA Training Inspector at the TRE Standardisation Course.
If you can fund all this (or get your firm to) and manage to pass the whole thing then I'm assured its worth it in the long term.
If I can help further - fire away.
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