The text is a little difficult to read but do you remember?

"Petrol tanks must be empty. The RAC will drain your tank at Liverpool, Fleetwood and Douglas (before embarking) free of charge if you are a member. Non-members are charged for this service"

Didn't they just, although I don't think it was the RAC who did the deed my first time over in '76. Being a local lad we'd sussed this out. Some people weren't happy though. alf