Bingo.
Thanks a lot.
I cant see why it wouldnt have worked, as it was just referencing the one from the other was it not??
but then again, it was totally redundant in this situation, i agree. So stripping it out has sorted it.
Edit:
HoriPotVal = analogRead(HoriPotPin); // reads the value of the potentiometer (value between 0 and 1023)
VertPotVal = analogRead(VertPotPin); // reads the value of the potentiometer (value between 0 and 1023)
this is the part i was referencing it with i think?
i put that in because i was going to try an centralise the pot value: ie, make central 0, rather than 500.
but that was before i took the controller apart and found that they were just straight up normal pots rather than something more complex