Fuel gauge/range issue
 

Hi. I have a V40 cross-country T5 (2013) and the fuel gauge is very inconsistent. For example, I can be driving along with 5 bars showing and then it drops to two and then back up a few miles further. The range also drops but doesn't rebound when the level goes back up.
I've no codes showing and it doesn't seem to be incline/driving style dependent.
Could it be a faulty fuel level sensor or is it likely to be something else?
I've just recently swapped out the fuel pressure sensor as that had failed.
Thanks