Handbrake fail MOT

Right my car is at the main stealers (Honda) where I brought it and thu have failed the cars mot on the handbrake. Now I have fitted new disks and pads 3 days prior and they are telling me that it cannot be adjusted any more than it is ! Now they want to strip my calipers down ... Why? They rewound fine and looked good condition, are they just trying to have me on or something?
 
Clio hand brakes aren't the most powerful, have you tried driving the car with the hand brake slightly applied to help bed them in, obviously, don't drive for miles with the handbrake on!
My BMW330 manual recommended this after fitting new shoes/pads.
 
Rear callipers are known for seizing, have you stripped them down properly? The pads most likely need bedding in properly too.