I found some fluid - someone was selling 500ml on ebay for a few pounds - and got up early on Sunday morning to top up the reservoir.
It was straight-forward - take the back seat base out, then release the back-seat back with the key. The key needs to be turned fully until the locks at both side of the seat back release.
Then remove the trim, the eight bolts that hold the plate on which the pump is mounted in place, tip up the pump on the plate and hold in place with a screw driver.
As can be seen, my fluid was way down. There are high and low level marks on the reservoir. I understand that the these refer to the oil level when the top is down. I used a syringe to fill the reservoir as the hole is a little small. I filled up to about the lower mark to leave space for when the top is down.
If there is an oil leak, it certainly isn't from the pump - the compartment the pump goes in was completely dry.
I've tried the top a few times and it goes down and up in one motion with no sign of fluid anywhere.
Easy job ... it took less than an hour.
Here are some photos I took ...