Where I live we're having problems with outsiders using our private car park. I've seen people park up and let themselves into their houses further down the road and also commuters driving into the car park in the morning and then walking down towards the station. They're completely shameless about it, and I don't feel confident challenging some of them either. If you saw them you'd know what I mean!

I've reported it, but nothing much is being done apart from a vague suggestion that we could have parking permits in the future, but it's not helping the situation now.
The point I'm trying to make is that this seems to reflect a wider trend in Forest Hill and it might be linked to the arrival of the ELL as others have suggested.