Have you had a dropped kerb put in as there isn't one on google maps? If not, the driver is perfectly within his rights to park there as it is not classed as a driveway. Your neighbour, on the other hand, who does have a dropped kerb could complain that someone is parked in front of their driveway.
Regular occurrence? Have you spoken to them or left a polite note under wiper? Are they there all day? Consider investing in a "No parking ,access required" vinyl poster next to gate. Always persue all amicable avenues first if possible 😊
About time you had a wash too.