Thanks for your help, Elly, and a great suggestion.
As I don't have a spare spray bottle (yet) I've been getting a bit desperate.
So this morning I twisted the curtains around. They have a white lining and Arny doesn't like it and hasn't touched them since. I dont think it's the colour putting him off, but the material of the lining which is a rubbery feeling.
Cheeta, if you have lining on yours maybe you could try that too. I'm only planning on turning them around when Arny is out of his cage.
If this doesn't last then I'll definitely go for the spray bottle.
Can imagine your frustration Bea as they see it as a great game. Everytime I chased Arny away or got him to step up, he came back. He was thoroughly enjoying himself