Transposed from the Ace/Aceca/Greyhound Forum - Filler Cap page 8
I believe the correct size of the tank filler hose to be 2 3/8inch I/D, which is 60.3mm in new money. The AC 3000ME uses the same size - with two lengths each of about 10 inch.
It is important to ensure the material is compatible with modern fuels.
When replacing the hoses on ME157 about 5 years ago sourcing unleaded-compatible fuel hose of this size proved challenging. I was fortunate that Spencer Lane-Jones in nearby Warminster was restoring an Aceca and had some spare.
The address below, transposed from the Ace/Aceca/Greyhound forum, might prove useful now:
"Talk to Alan at:
BEECHGROVE ENGINEERING LTD
7A, PLANTATION ROAD
LEIGHTON BUZZARD
BEDFORDSHIRE LU7 3HJ
Phone: 01525 382953 01525 382953
Usual disclaimer."