Absolute complete tangent, any chance you can get some photos of how the lower part of the radiator sits in the subframe when you get chance? That sits far tidier than the one in my Megane conversion does.
I got a cheap pattern standard Clio one off Ebay because Meg rads don't use the 197 mounts anyway. Its made of tinfoil and is significantly lighter than the holed OEM one I pulled off it lol.
Autodoc been bang on for me, although its definitely a planned maintenance site, lead times can be a bit inconvenient if you are working to a deadline.
Permanent fix is mechanical sympathy and making sure the the slave is installed and bled correctly. I've found they really don't like being pressure bled.
Another option not mentioned above is a Megane RS Swap, I bought my conversion package for £1700 with an R26 LSD gearbox.
Left hand one on your diagram should be going to a carbon canister solenoid down the drivers side of the engine. You can throw that in the bin.
Right hand one is the brake booster vacuum feed, hook this up to the engine in some way. Dont worry about a 1 way valve, the Clio already has this on...
I've been weighing up one of these for my meg engine when it goes back together. I'm pretty tight on space infront of the oil filter with a Megane Radpack as it is so teeing off the existing sensor looks a better option for me.