I was going to say that I thought these have a weird shock size don’t they?
Checking they are seemingly 165×38 (older original) or 184×44 for TranceX and they do seem to be available (new). Though seemingly you are limited by what RS shock you can get in the 184×44 length (going by the RS site)
The Fox R should be a “propedal” shock unless it’s a really early version. Personally I’d get it serviced, and while doing that get it tuned to the required riders weight/useage
I’ve yet to be convinced that any other air shock (other than Cane Creaks new one) is as good, don’t get me wrong the new RS stuff looks good & we can hope it turn out so (more cheaper choices) but there no long term tests yet or any shouting it’s loads better than their old fox…