TB
There is no reason someone of those qualifications could not teach, as long as the CGI checked he knew the material. I had no more formal aviation-directed academic training than that (just a few more hours and a CPL/IR) and was very comfortable teaching Gen Nav, one of the hard subjects, and have had a lot of success in some trying circumstances. That is because of the non-aviation side of my background.
I would also defend Colin and Brian, his CGI at SFT on this one - the Gen Nav instructor problem at SFT was really because they couldn't find anyone to do the job (I was a student there at the time, effectively teaching myself and relying on Royal Navy training). I was the solution, as I started working as soon as I could to fill the gap. I have heard no complaints about the instructors at EPTA.