One question:- does the same poorly performing supplier carry out the training?

Why not deal directly with the manufacturer?
Meanwhile, this is the second post recently that has mentioned "refresher training". I'm guessing this could be the latest money-making tactic by the "companies that care" (or is it yet another OTT interpretation of an EU regulation).

Not sure about "tried and tested" (apart form the MS-16A, of course), but other possibilities are available; the
Micrel for example.
I seem to recall that ZiMed was taken over by Cardinal Health (...CareFusion); I'm not sure what became of the Alaris AD.
See
this ancient document.