If all else fails poly sheet and rope is very cheap, lashed with rope side to side over the ridge plenty of times to prevent flapping it should last the winter, depending on your wind exposure.
Good practice for the coming present season too
https://www.scaffolding-direct.co.uk/tarpaulins/
https://www.scaffolding-direct.co.uk/tarpaulin-accessories/
I was gobsmacked at the prices of decent tarps. On the other hand, old lorry curtainsides are really cheap and bloody tough. One side would probably yeild three roof coverings and last for years.
Tarp ordered, and I will get it fitted some time over the next couple of weeks......
.....so only want to do it once this winter (and not so painful for the neighbours to look at).