When I first came to France we were younger, so were in the system on our own accounts and with various changes ended up in PUMA with our caisse being CPAM. My OH being older than me did get his UK state pension a couple of years back, so I was able to piggyback on this benefit too.
I guess there is an unanswered question as to whether officially we are still in PUMA, and it is just that the bills get paid by the UK. And so, should that stop we will automatically just pick up the bill ourselves without any fuss or bother?. When we got the S1s we didn’t do anything but send in the form and then update our cartes vitale, so if it comes to that I hope it will be just as easy in the other direction.
(And for Joyce, the fact that people with S1s don’t pay social charges on their pensions is to due with tax law, not health law. )