model in question 2005 R53

After a recent fuel filter change the fuel gauge takes a long time (say 1/2 hour) to return to full after refilling.
It only does it if I fill from below 1/2 full or near empty, if it is above 1/2 full & I refill the gauge goes straight to full.

You can either drive for a while & it will very slowly return to read full or I have found by resetting the ECU it returns to full. I have been resetting the ECU via the onboard menu & it's a pain in the next to do each time.

I have taken the filter housing out again as I thought something maybe fouling the sender but all looks ok.

Any suggestions??