After a day of waiting in Penrith for our golf to have it's seatbelt fixed, I came home to fix the beetle. Emil helpfully picked me up from the station and we came home and pitched into it. He's a master wiring man and we knocked it over in not long at all.
One of the main pipes coming from the filler neck runs about a metre of tube into the inlet of the pump. We filled the filler neck up with coolant with antifreeze. As soon as Emil turned the ignition on, the system started bleeding itself. In the end, we put somewhere in the vicinity of a litre of coolant into it.
I guess the next trick is to see what difference it makes to intake air temperatures now the fluid is actually flowing round the system.