@Nick-Carthew It is just &"r'(è§é"§"è!ç&çé"!çà annoying that all those manufacturers keep inventing their own "standards" and leave it up to the final users (or the smaller companies squeezed in between) to sort out the mess.
I guess that my next GPS (when the TT400 dies) is going to be a rugged tablet with MRA Nav. That cuts out at least one layer of complexity. Just a pity that MRA Nav only works on android and iOS?
Have you ever experimented with a windows 10 compatible USB GPS receiver?