Just an update to this...
Fault code still comes up, even after clearing it 2 times and scanning about a week later. Car still drives fine and changes gear ok.
What should I do? Try and trade in because it might get worse? Or just hope that it's just a sensor throwing a hissy fit most of the time? I read somewhere that the gearbox uses a secondary sensor of the first one malfunctions as a backup, but can't remember where I read it.