Advice on unacceptable noise issue

Other

Hi There,
I'm actually after some advice for my sister who is having a horrendous time with a tenant in a nearby flat. She lives at Nine Elms (Wandsworth Council) which is a 19 story communal building ( Embassy Gardens) with concierge. She is a private renter and pays her own rent. There is one tenant playing booming loud music regularly between 1am - 7am in the morning. My sister is wondering what the best course of action would be. She has emailed the concierge several times and they are aware of the situation but nothing has been done about it. She hasn't notified the landlord, police or council yet as she's not sure of the best course of action. Is it illegal for a tenant to be making this amount of noise throughout the night? Any advice would be hugely appreciated. Thank you.