Knocking down a wall to create a driveway requires planning permission.
The planning permission will require that the footpath by dished by the Council.
Some people get planning permission , but then ignore the requirement of getting the Council to dish the footpath.
So, first check online to see if they have planning permission.
If so, check with the Council how much it would cost to dish the footpath.
If they don't have planning permission, check other houses to see if they applied and got it. If so,chances are you would get retention.
Factor all that into the price you pay.
Brendan