MSF is real
Honestly, one of those naval forts wouldn't be too bad for an extraterritorial PMC. It's tiny as fuck, but it gives you room for a helicopter and theoretically you could do missions within a fair span of the area of the fort.
The real problem is that they're all around the English channel, where nothing happens that would get a private military a job.
It'd be tricky to defend, if anyone really wanted you gone they could just bombard the place.
What made Mother Base so useful was that supposedly nobody knew exactly where it was, and the few people who did were helping to defend it.
It would be useful for arms/drug/human trafficking though, or as a training facility, or FOB, at least until a country launches a straight up invasion.
It also probably helped that Mother Base, being a former oil rig, was always out at sea somewhere, not close to the cost like a naval fort would be.
Personally, the idea that no one knows where it is is rather silly, since they almost definitely require shipments of food and other supplies from the mainland. Even trusted suppliers could be bought.
If it weren't for trouble of fuel, a ship would make a perfect choice for a mobile base, especially if by some miracle you could maintain an aircraft carrier.
Not posting the actual msf. Just fuck off.