Hello, I know it's a while after you posted, but I wondered if you ever resolved your handbrake issue? I have a 2014 S Max and today parked on a slope and left the handbrake on. I returned to the car after a couple of hours to find it had rolled down the hill and into a telegraph pole, causing considerable damage. The handbrake was firmly on but the car was not in gear. However, I would think the handbrake should still hold.
I have a feeling it will be assumed I left the handbrake off but if I had done so, the car would have started rolling as soon as I tried to get out, which it didn't.
I am going to e-mail Ford about this but I am trying to gather as much information as I can before I do. Any information you can offer would be greatly appreciated.
There can be cases where the handbrake backs off over time as the brake discs contract as they cool down, possibly enough to be a problem when parked on a slope.
Design of the handbrake system should take this into account but never seems 100% robust. Car makers often try to cover themselves by putting info in the handbook that says always leave car in gear when parked on a hill, and wheels angled towards the kerb.