Yes Ian, I know that problems with midi specs can arise.

In my case, my Technics KN7000 talks to my MS40 without problems - so does my Roland EM2000 - have controlled both the MS40 & the Technics with that. However, I don't ask the midi to do a lot - change voices for instance on the MS40 using the MS40's own panel.

But midi spec standards are now slipping badly. When you consider how long it is since midi was implemented, it shows that the manufacturers care little for the concerns of their loyal customers and nowadays do the bare minimum they can get away with.
The midi specs on my Tyros3 are a joke.
Tony