First up, karbo you've been as massive help and it's really appreciated!
Long story short, my main take-away is that this thing's pretty finickity to set up! A couple of times the thing even seemed to be bricked.
After multiple attempts and reboots I'm pleased to say I did manage to get firmware installer working - big thanks! You're definitely right about it not downloading and it ran all the way through eventually. Weirdly though if I now run the current Universal Control software it says I'm still on version v1.00 but that seems like it could be wrong and just unable to recognise an older version.
But... after updating I still had exactly the same problem. I then tried the XT driver and BOOM - the Faderport is following track selection!
Now I think I should have tried this first - looks like I was possibly lead down the wrong path by some users saying the firmware was the issue in this thread? But even then, it's still a mystery that the standard driver doesn't work properly with my unit.
I wouldn't have got there without your help karbo - many thanks again for your time. Very happy to have this thing working.
Ben