Help: horror movie

I think the movie is about 5 / 6 years old.

It's a horror movie set in English or Irish suburbs, the ones where you don't wanna come out at night. It's about a guy and his younger sister (or brother), the youngest one is home alone (in appartment building), the brother has missed the last bus because not many buses are running to this part of the city where nobody gets out at night. While suspicious people are circling the appartment building or entering or something.

Anybody can help with this? I don't know much else what happened because I never got to see the whole film.

Haven't seen it but Attack the block sprung to mind

Same! I didn't reply because it seemed too different, but I should have because a lot of these things are half-remembered mashups of multiple films, anyway. Definitely check out Attack the Block.

Its not Attack The Block. Though it indeed is a very similar setting.
The movie I'm looking for seems however more indie, genuinly horror and mysterious with a slow pace.

Or if anyone can recommend a complete movielist per genre so I can scroll the list for a few years? :-)

No idea how comprehensive or not it might be:
2010s horror movie list

I found it. Probably described it totally wrong. It was Citadel (2012)!

Thanks for the help, put me on the right track.

Yeah, wouldn't have guessed that one from your description but that's as much down to me not connecting the dots, glad you found it