[Bagheera]

Just an update:

The garage found the new Dayco water pump to be faulty. The pulley would turn but the impeller wasn't moving! I saw it for my myself. They've fitted a new water pump at no cost to me. The low coolant was down to it boiling and evaporating.

I've just come back from a long test drive and I'm pleased to say all is as it should be and no overheating.

Average MPG has now gone up, back to a what I would consider a normal figure (45mpg).

Thanks for all the input!