Slight Drift Warning....
I have recently changed to buying Esso Premium unleaded. Why? The pump is labelled E5, BUT according to the ESSO web site:
"Although our pumps have E5 labels on them, our Synergy Supreme+ 99 is actually ethanol free (except, due to technical supply reasons, in Devon, Cornwall, North Wales, North England and Scotland). Legislation requires us to place these E5 labels on pumps that dispense unleaded petrol with ‘up to 5% ethanol’, including those that contain no ethanol, which is why we display them on our Synergy Supreme+ 99 pumps."
https://www.esso.co.uk/en-gb/fuels/petrolI have noticed an improvement in MPG, by about 10%. The cars seem to be running better, too. I know Morgan cars do not need 99 Octane fuel, but if there is an ESSO station near you it may be worth a try.