its very possible that this has been covered already but any suggestions for making cloaks for riders of Rohan but out of anything other than green stuff

Long shot, but you could try actual fabric/paper, soaked in pva glue. It should set with some degree of pliability to get the pose right. Don't take my word on it though, no idea how it would work out. To be perfectly honest greenstuff cloaks are easy, I hashed some together with no experience a year or so ago. They're far from brilliant but effective enough once painted.

The Fireforge Tuetonic Knights have seperate capes that you can use. There's a company called Hordes of Bits that sells parst if you don't wish to buy and entire box just for the capes.

I used them on several different figures and was happy with the result.

many thanks to both of you both great suggestions, will have to try both to see which one looks like my imagination.