I installed a couple of new Pro channel modules, however X2 wouldn't see them.
It turns out the Pro channels won't register in X2 unless VST scanning is enabled under preferences.
Since when does a Pro Channel module become a VST plugin :-). Guess cake needs to label this properly under preferences - I shall report a bug...!
One of those things when it's easy when you've jumped over the hoop... I post here in case somebody has the same issue one day.