Any reason why is has to be TDI as apposed to an instructor from another agency?
yes, the course is offered to technical divers thru TDI as a specialty course. Thus to be an instructor for the HOG/TDI Repair Clinic Specialty you will have to be a TDI instructor.
TDI stepped up to the plate to offer this unique in the industry opportunity for technical divers to get trained to service by approving it as a sanctioned specialty.
It is not a comment of any type on other agencies, in truth I did not approach every agency and there may have been others that would have participated and indeed there is one other that is working on a program. However that oneis not done yet, so the only approved clinic for divers is offered as a TDI specialty.