My drive is wide, two and a half cars width. My next door neighbour reverses off his drive and swings roundbackwards into mine, doing a three point turn, so that he is facing the right way to go down the road. I don't mind that at all, except that when he pulls away off my drive he drives over the top of my flower bed. I have now placed three rockery stones on the garden to protect my flowers. If he damages his car on them am I liable in any way?
Have you checked your deeds (and his) to make sure that either of you don't have a row or easment over the others drive?
If no such clause exists and having an open plan drive is an advantage to you then I would be tempted to put up a boundry marker that may (or may not) allow him to turn.