Is there any way of finding out who lives in a property?

The owner and who lives there may well be two different matters? I think the OP might be referring to fellow tenants?

Knock on the door & neighbours..

Knocking on the door and asking around the neighbourhood are really the only reliable ways.

Search online for news articles with the name of the street or the estate and you might find some relevant information, though...

Check the Register of Voters. They may have registered to vote.

The electoral register is organised by street. Whether you can get access to it is another question. I wanted to have a look at it in the library one time and they were reluctant to share, I'd say because they didn't understand which version they're allowed to share and which they're not.

I'm thinking about the physical copy, which is supposed to be available in libraries and maybe other places.

It hasn't been printed for ten years. And the info for houses is sometimes a further decade out of date as the rights to use the full voting register for that purpose were removed

Thanks, I'll check it out.