Ok. Looking at the pics it's quite easy to see that this guy can get both his Landy and his van on HIS drive. Also, as a medium, he can park his van across his drive, face on, and if he needs to get the Landy out he just moves his van. At the very last resort, the space can be moved 3' to the left and placed at a slight angle, sympathetic to the acces to your plot.
I think it's simply a case of meeting with this guy and saying it exactly as it is, as he's not exactly going to be massively put out by moving over a bit, or parking on his own drive.
Go knock his door, and just spit it out. . You'll feel much better when you know where you stand. .