Scenic II rear Brake Binding.

I have a 2005 Scenic which I took for an MOT. It failed as they said the rear Discs were worn and brakes were binding.They said it sounded like the Calipers were seizing and not releasing. I told them to put on new discs and pads and check the Calipers. Later they rang me to say that they had changed the disc and pad on the nearside and cleaned up the caliper and it was now releasing but they had to put a new caliper and disc on the offside. However, this side was still binding and they said the Handbrake motor was the fault and needed replacing at a cost of £500 !!! Now I am not a Renault expert but I would have thought that if one side was working fine and releasing then the Motor must be ok ? Could it be the Brake Cable to the side that is seizing that is causing it to bind and can the cable be replaced without replacing the Motor ?

Scenic II rear Brake Binding.