I love a good widdle.
I saw Rush about 8 years ago in Manchester. they were fantastic, but I do not remember pay anywhere NEAR that amount. Yeah, it was eight years ago, but, hell, its not that long ago that £65 a ticket is now acceptable.
I think you need to look at this like a professional would and a pro in this case would be an upholsterer. I am thinking a shell for the front and back which could have the material tightly layer over it and stapled underneath and would come together like a well fitted casing. Total ball ache of a job