Thanks for all your comments. At last got around to taking the hinges off the near side for painting and propped up the roof as advised.
Connecting bolts were easy to detach.
(I took care to take pictures of all the hinge struts plus measurements to ensure I had them in the correct configuration.)
However, upon reassembly I am now having problems re-aligning the holes as per reverse of dismantling.
I suspect that although the correct height of roof was maintained by my three wooden props, the gas struts are possibly pushing the roof too far forward.
I would be most grateful if anyone might pass on any tips for ensuring correct alignment.
Many thanks.