........so far fuel and temp sender units have tested ok. Rear earth is ok as are the earths above and to the left and right
Those would be my first suspects. I have had an intermittent fuel gauge on the Roadster since buying it a couple of years ago. I have also checked the earths (they are OK), but my OBD-II 2 reader occasionally still tells me there's a problem on the sender circuit. One day when I'm feeling brave I will remove the sender and check it. I have used this product
https://www.amazon.co.uk/dp/B084CW1LZ9/ref=pe_27063361_485629781_TE_item?th=1 which is recommended for freeing-off sticky fuel senders, and it does seem to bring some life back to the gauge. I know the range is 250+ miles, so I brim it when re-fuelling and take care to find a filling station after 200 miles.
