The off-centre tightening bolt of my Lockjaw finally rounded out so the Allen key can barely turn it. It seems to be a common failure of the part.
I was able to get a spares pack pretty easily in the UK. This is sufficient to replace all the removable parts of both hinges.
The new OC bolt, which is of good quality had some minor changes in design, so I also switched the pivot bolt that it slides into. All the other parts were unchanged.
Its an easy to do, 5 minute job and the new closure is very solid.
I downloaded a pdf of instruction from Thorusa but they seem to have been removed. I still have the pdf if anyone needs it but better ask the author at Thorusa