I have spent the last three days lowering the hull, to 6" off the floor in the tent. It's now down, all level and squared up, ready for the next step.
About a third of the time was spent figuring out how to get the thing down, safely and without damage. Another third preparing all the safety props, blocks, and ropes I used to ensure nothing would slip and crash out of control! The final third was actually lowering the hull, using two 2 tons trolley jacks out of the three I have. I didn't want to take the risk of using 3 at the same time, it might have been quicker but there was the risk of the jacks toppling, so I only lifted and lowered with one at a time. Slow but much safer.
So now it's done. I am going to be able to get on with the cabin over the winter.