I managed to be passing when the owner of this FC in Poole, Dorset, was coming out of his home, so I stopped for a chat.
The owner, Ray, had both the cover and the original roof remade by a local upholstery company in Poole in Jan 2018, as well as some seat refurb. To my untrained eye, the quality and fit looked good and Ray was clearly very pleased with both items. The upholstery firm has a Facebook page which states they do work on cars/bikes and marine, although they specialise in furniture. I sensed the work wasn't cheap, but the company do seem to do a lot of high end, quality stuff, just having taken a peak on their Facebook page:https://www.facebook.com/jvupholsteryltd/
Contact details are all there, as well as further pics of Ray's FC with WIP (scroll down to late Jan 2018)
Hoping this might be of use to an FC owner somewhere!