Thanks for finding my earlier post Richard. I have been snowed under in the office and hadn't had chance to dig it out.
It strikes me that if SimonH is correct with the CX having an actual capacity of 43l, I have actually got 16l left in the tank when the gauge reads empty and the warning light is on (Never been able to get more than 27/28l in). Nice to know that Morgan are looking after me and want me always carry around that 16litres/12kg of fuel that I can't use in a light-weight sports car
