Morning, and thanks for the quick and detailed reply!
I spent the day yesterday, experimenting with the Pro Gateway (it’s quite surprising that it is permanently bonded to Arduino’s ecosystem, given that Arduinio is quite open-source minded). Anyway, from peeking into the official Arduinio image, I found the reset pin designation, and this matched with what I found by physically tracing the connection on the boards.
So, with that information, I set about setting up the software, using the guide from TTN for the iC880A board (also SX1301 based). After much experimentation, learning and poking around, I had, unfortunately, no luck. The packet forwarder reports ‘failed to start the concentrator’ and stops. I also stopped at midnight 
I know the board works, as it communicates nicely with Arduino - shame it can’t be persuaded to talk to anyone else! I might give one final try, but ultimately, I might have to put this board to one side, and invest in a gateway that is a little more configurable (a RAK product, for example).
Again, many thanks,
Chris