... Off to Sainsburys to fill up, and could only squeeze 44 litres in -
You're a braver man than me then Mark, I wouldn't let supermarket fuel anywhere near my Morgan. BP or Shell premium are the only two I trust (or at a pinch Esso). Are you using a lead replacement additive as well?
With regards to the fuel gauge, I did once have a nervous journey looking for an open service station but it managed at least 25 miles with the needle on zero without running out. I've never checked the capacity though.
~iw