Thanks for that Rupert. Just need to work out what the French is for 'Spray Brake Cleaner' is. Good point to leave it on blocks- I have to raise it up anyway to reset the brakes, so I'll just leave it there with bags on the wheels.
Taking the hubs off is a big job according to the manual. The nuts are a huge 46mm (1 13/16") A/F and the torque setting is a whopping 350Nm so we've had to buy a new torque wrench and socket. Unfortunately, because of the backplate design, you couldn't get any spray into the drums without removing them first.