I have the usual 'up and over' garage door. Since the drive and garage were built in the 1930's when cars were only slightly wider than a bath tub it is pretty useless. Are there any rules about removing the door and bricking it up so I can use the garage as a potting shed/man cave :-)
Generally planning consent wont be needed...if its detatched you should be ok ..but if its part of the house and you plan for it to be part of the living space you will need building regs approval.