We saw the queue for the bus(es
) to Arnage at the main gate and were told "One and an 'alf hours..."
"Sod that" thought us, and walked down to the Porsche curves instead.
The whole thing seemed a bit daft, although I'll be trying to get an Arnage and Mulsanne parking ticket for next year. Assuming they persist with the inefficient, irritating approach of only using shuttle buses.