…via a manually entered "Static Route" in pfSense...
So Chris - have I made it more confusing?
Oh boy, I was busy recently. Didn't realize that I was that far off the track…
Of course, a static route in pfSense makes perfectly sense and is the missing brick I was looking for.
Thanks Jason for your rather long explanation! Even I got it now.
I shut up now and and have some sleep... :-X