The purlin ring was glued together on the yard, chocked up so that it didn't twist on the slope, then held firmly together with the strop. (for non-British readers, in the UK the 'yard' means just the hard surfaced area outside the back door - everything else is the garden! It gets very confusing at times when blogs talk about their yard, then show you the garden!)
Moving swiftly on from discussions on the joys of a common language........!
The purlin ring.
We roped in several of our strong male friends, Garth, Big Dave and Big Dave's FiL - Pete, to help with the manouver. The next 10 photos show how it was done. Apparently it would have been a lot easier without a big deep pond in the way!

Once the purlin ring was safely in place and tea and biscuits had been devoured by the workers (got to look after your staff, you never know when you might need them again!), Himself took all the 'bird's beak' wedges he'd saved when he'd previously cut them out of the rafters where they rested on the main beams. He turned them over and glued them onto the purlin ring under each rafter to give extra support - always thinking that man!
and tried it for size! It fitted - naturally!
He put the corner wedges in place.......