... all grades are treated as separate jobs ...
Yes, that's a very astute point. But techs can progress through the limits of the Band, can they not? Beyond that (as has been mentioned a few times already), they will need to apply for other positions, possibly located elsewhere. The same as everybody else in the UK, then!

On the matter of training, to my mind it matters very little (in fact, not at all) how a tech was trained, what route was taken, or what the course(s) were called (even if the "training" was "only", in fact, by way of hard-won experience), just as long as he's ready, willing and able (capable) of doing the actual job before him.
Yes, biomeds (or whatever they may be called locally), being support staff, are undoubtedly "poor relations" when compared to the medical and nursing staff. But (again, to my mind) that is only right and proper. After all, patients are cared for by nurses, not engineering technicians!