The people parking across your drive are causing an obstruction and you can report them to the police. I doubt they'll do anything, but they just might.

You could try applying to your Council for an H-Bar marking in front of the drive. It means little, but discourages people and will provide more evidence if you want to keep complaining to the police.

All the stuff about drop kerbs is just to get rid of the people that knock out their garden wall and drive over the footway to park. As your access is directly off the highway, it shouldn't be an issue.

If the Council won't let-you have an H-Bar, write to your local Councillor asking for help. If that doesn't work, get a photo in the local paper pointing at your drive and looking sad.