Just to update
Drove the beast around a bit yesterday and deliberately used parking brake as often as possible. Normal use, just flick out the handle and let the system operate, just evrytime I had to pull up.
Some involved hill stops but nothing too steep.
Just before I got home I deliberately stopped on a steep hill and used the parking brake. Minor squeak, no screaming sound and no fault warning.
So tried it a little more and even the squeak disappeared, no sound other then the normal purr of the brake unit operating.
Took advantage of the peace and quiet and bunged it into an MOT this morning.
Brakes passed with flying colours
Failed on anti roll bar link and steering rack knuckle joint so not all good but relatively minor in comparison to the black hole of the parking brake system.
I can only assume that the parking brake electronics found the movement/load with the new caliper more to it's liking and adjusted itself to suit.
So, a set of rear pads cost me two calipers, a set of cables, a can clip test (independant) and a boat load of heartache.
Apart from the heartache, some of that was needed and still far cheaper then some of the costs I've seen people charged by Renault.
What I've learnt.
You can get secondary handbrake cables for the 5 seat scenic, despite both my local renault dealerships denying it. Part number 7701 478 158
The system "balance" will upset the electronics but this doesn't mean that a new drive unit is needed.
That Renault service (at least in my area) sucks if they are asked for advise. Book it in and we'll test it (and charge you) doesn't help when all you want to know is will plugging it in allow reset to parameters after a pad/cable change.
I'm also told that there are two differing rear caliper set-ups for the scenic/megan range. One for Electronic system and one for the manual handbrake system.
The difference being solely in the abutment and arm stop positions. So look carefully if you change one as a manual brake caliper on an auto system can cause problems even though it seems to fit. (Thanks to Mike at Brake Engineering for that tip)
That TRW remanufactured calipers no longer have the external spring, it's an internal coil spring.