Inconsiderate parking by council tenants - parking not allowed by council signage on verge

My neighbours are continually parking their three vehicles along the road, often opposite the entrance to my dropped kerb driveway, meaning that I cannot access it. (I have two cars parked off road on my drive), whereas they do not use their drive. I am often unable to park my car in my own drive, and hence have to park on the road further down. There is a council signage restricting parking on the opposite verge which is never adhered to.