I know I shouldn't laugh but that bike you've got on loan.............I bet you've got ya knees up by ya ears when riding that cos ya not exactly short are ya.
Good luck with the garage. I've just had a chat with my mate and he said that a chain and sprocket can be fitted in less than 10 minutes. Christ knows what else they are doing to warrant a massive bill like that. Exhaust valves don't take long to check either if that's what they are doing.
Give 'em hell fella.