Andy, try CC Performance Engineering. I got a couple for my CB900F-5s. I changed out the main bolt for a stainless one. Just put the bolt in the lathe, rounded & smoothed the bolt head and used a nice dome nut. Works a treat.
From their Facebook page:
CC Performance Engineering
Garage lane, Setchey, United Kingdom
01553 277 273
07432 707 273
EDIT: I also found Items for sale by camchaintensioner_co_uk | eBay
I'm thinking of these now. They look(?) a little better than the threaded bolt type. Hopefully they might have what you are looking for. Be careful not to slip the timing as I did on my T'Bird Sport!
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