It became apparent that the drive had never been dug out and made up properly. Previous owners and ourselves have been simply adding tonnes of gravel every few years just for it to slip slowly and silently down in to the ground.
The winter of 2012/13 was also wet and we lived in a semi-permnanent state of flooded drive and all that goes with it - including lots of mud. So, web bit the bullet and went for a new drive. We liked gravel, its not only environmentally sound, its self draining so lets water move away from the house. Gravel doesn't work on slopes though, so we went for a black limestone at the top of the drive leading on the the drove (with a drain to catch all the water that streams down off the drove when it rains) and as edging and hard standing in front of the front door. The black limestone is a similar black to the black brickwork on the front of the house.