Hello all,
second attempt up at the shed yesterday, this time success!
Managed to get one out of the two sections up and in place, with the help of a mate (Pete, as you say, it's certainly a two man job).
What surprised me was that it doesnt seem to be a compound curve at all, which makes life a whole lot easier.
I tried to post some pics of the process, but couldnt upload them, in summary gentle steaming at each end with a kettle with the lid wedged open worked well. I made sure the surface going in first was painted to avoid sucking up damp when in place