Disco 3 (LR3) Handbrke wont release

the handbrake will not release when switch is operated and ther is a noise like the starter is not engaging on the flywheel( I know the sterter and ring gear has noting to do with the parking brake but its just the noise it makes.is this a common occurance and is a new park brake motor the cure?

There was a recall by LR to carry out a modifacation to fix this issue, although I know some one that is still having a parking brake problem now and again, and his D3 is fully maintained by a LR main dealer, perhaps he's unlucky.
First check if the recall work was carried out on your vehicle.