I live in a relatively nice area. Get on well enough with my neighbours at the front but this issue has to do with the back access to our house and the garages surrounding it (most of the owners we don't know. I saw owners but we all rent them from the council).
We are very fortunate to have back access to or garden with gates and a hardstand with enough space to put one car. It's all above board, checked the planning and with the council when we bought the property and have right of access to it.
Surrounding this is like a cul de sac of garages (how do I put a diagram on here?)
We also rent a garage, and we're not supposed to park outside them so OH's got a car in there that we're doing up.
One of the garage owners has a van that is too big for his garage and parking is awful on the streets and so he parks it in front of his garage. The space is not very big and because of the length of the van the person who's garage is opposite would have real trouble reversing in or out of their garage (saw that neighbour one day and apparently only uses it for storage and was okay for him to park his van there) so I thought okay, fair enough he's not impeding our access or anyone else's even though you're not supposed to park there I know how bad the parking situation is not really any of my business. (I've also seen cars parked in from of garages there for maybe 1-2 hours at a time that are probably visitors. Again, fair enough.
Sorry that was long but it's all relevant to the next bit. I had a friend pop over to visit, she was literally coming over for an hour, so I told her to park in front of MY garage (everyone had good access to get in/out apart from the van man but he is never usually home on a weekday at 11am so thought it would be fine)
Half an hour into my friend's visit I hear someone beeping their horn out the back. I go out to investigate and he's hanging out of the window effing and blinding as I walk out, asking me if the car was mine. My friend said it was hers and he said "well you need to move it so I can park my fucking van" he couldn't get the swing to park It properly in front of his garage.
He was quite intimidating and my friend went back to get her keys and I asked him if he could stop shouting and that it would only be a minute.
All I got back from him was "I need to get my fucking van in you silly fucking c*nt my son is sick"
I then realise his ~4 y/o son is sitting in the passenger seat. Now I definitely know how protective I get over my kids when they're ill but there's no need for that kind of language.
My friend returns with all her stuff moves her car and apologises that's she's going to just go because we'll never find another space and she doesn't dare leave her car there again. It's all over in about 5 minutes and has been blown ridiculously out of proportion. I offer my apologies to the man but he just grumbles and swears and mumbles about entitled arseholes 
.
I go back to my garden, lock the gate and get on with my day albeit a little bit rattled.
A couple of days later I open my gates to find another van in from of another garage, and both vans are now parked in such a way that I can't drive my car out of my hardstand. I've caught sight of him in and out of the back of both cans from my bedroom window so I can only assume he's hired another garage in order to park a second van to deliberately try and block us in. Luckily he still goes to work in the bigger van so can get out during the day but no way I'd be able to get in if I got home later than him.
I've been on to the council about it and they said they'd send enforcers round as it's a no parking zone but that hasn't happened. Twice I've tried to knock (with DH in tow for support) and he hasn't answered. I just don't really know what to do at this point 