Compliments of the season one and all,

Just a final update to this thread to complete it.

As a side bar, my car has that annoying stop/start function and recently, I had regular warnings that the battery was not fully charged to allow the stop/start to operate. Bought one of China's finest testers which revealed that although fully charged, the state of health was around 30%. So bought a new battery and fortunately, kept the old one.

Took delivery of an accessory socket with a one foot tail. Hooked it up to the old, but now fully charged battery and the tire pump worked like a charm. Expansion tank pressure now around 2.75 bar with the pump operating as it should. Could have achieved 3 bar easily, but probably not necessary.

Obviously, the additional 5m of three core cable with its associated increase in size was creating quite a large resistance.

Bottom line, job done.

Have a cool yule!