I might get a couple of stickers made up "Maritime Gendarmerie", might speed things along a bit
I've been reading a bit about locks on the Seine and other parts of France, there seems to be a number of different construction types, each with their own hazards. Low sills protruding from the bottom of lock gates, floating bollards that jam up in their runners etc etc.
A common practice seems to be using sheet piling for the lock walls, ie. corrugated shape. The problem there is fenders tend to locate themselves in the "inny" bit, leaving your gunwales up against the "outy" bit. Hence why people use scaffold boards outside of their fenders. Plenty of rib fenders would be a good idea but as smallish boats we should be able to fend ourselves off anything dodgy without too much trouble.
The thing to remember is there's a huge amount of traffic continuously up and down the river, commercial and pleasure. If they can all manage it without too much difficulty then I'm sure we can