Thanks Andy - thats my plan A.
I spent an hour this afternoon unfastening the straps and cleaning it all up while I sized up my options.
I have noticed the threaded fastener at the end of the belt is pulled over at a strange angle as tension is applied. As another option I am considering fitting spacers to these fasteners to keep them at right angles to the chassis as tension is applied , so gaining a useful half inch or so.

Also the threaded section seems overly long ( about 3 inches ) when all it needs is about an inch. I wonder why they kept them overly long. Not really an issue , just took forever in the restricted space to spanner the nuts off!