I moved into my HA flat a few months ago (bought), it includes an allocated parking space. At first lots of cars used my bay, one person even parked for 3 days solid!
I don't personally own a car so I didn't complain but after a while it became an issue for my guests especially as parking is very tight around here, plus I'm paying for the parking management charge only for other people to use my bay.
A month or so into lockdown I put a cone in my space (another resident has done the same too as it's common practice sometimes). I noticed that people were moving the cone and parking there!
It turns out my neighbour has been running a salon in her flat throughout lockdown as has been telling her clients to park there 
. I spoke to her about it, at first she lied and said it wasn't her then she backed down and said it wouldn't happen again.
A few days ago I went outside and saw someone had done it again! I went to put a note on the car and saw someone was sitting in it so I walked up and spoke to her (she was scrambling to put the car into gear smh), she told me the neighbour said to park there but only if she was quick. 
AIBU? I own the space, there's a cone but she still feels entitled to it? IMO it's bloody rude. She's generally a pest to others so her stubbornness doesn't surprise me.