if you really dont want to risk any form of confrontation or funnyness over this, you could just go out in the car several times a day (dont know how convenient it would be!!) and keep going to their door saying "i'm so sorry to bother you but please move your van for a sec because i need to get my car out/park my car"
dont ASK for the van to be moved, just politely say move the van for a minute.
pop out at 7am a couple of times (if you can!) and maybe go out, come back and go out again half an hour later! just keep this sort of thing up for a bit and each time just again say please move the van for a sec cos i cant get out with it there.
the idea is to make keep moving the van a pain in the arse for him! that way, he will get sick of keep moving it for you and the idea will come from HIM to not park it there anymore, so he has no cause for being off about it!
but if it were me, i would just say oy, arsewipe, dont park your rustbucket here again or you'll turn up in a&e with it halfway up your bum.
which tells you why i have no friends.