The Highway Code's Rule 243 states that you should 'not stop or park where the kerb has been lowered to help wheelchair users and powered mobility vehicles, or where it would obstruct cyclists except when forced to do so by stationary traffic.' Parking a vehicle fully or partially across a dropped kerb is classed as an obstruction and either the police or local council can enforce the contravention. Based on the resources a particular authority has in dealing with this, attention will usually be focused on offences that impede those with disabilities. Complaints can be made to the local police via the non-emergency 101 number, although it's usually better to contact the local council first. If the problem persists, the council can mark a white line below the dropped curb. However, the markings aren't enforceable by police or councils - they're only an advisory area as where not to park.

Essentially, if he's stopping you getting in or out of your driveway - he's causing an issue that you have the right to report.