I had a similar issue, living a detached house, kids screaming and people chilling out all day in the garden, People going in and out the house, was about 8 of them living in there with kids only 4 bed house, this was going on about 1 year i had enough as i just recently purchased the property lovely street just these idiots started to rent after a few months after I moved in. Council was paying for the rent which was over a £1000 pounds a month.
Sent them a letter don't think they understood it as they didn't speak much English. Spoke to the Landlord he tried to make them stop making so much noise, but still went on for ages, he didn't care much as long as the rent was paid. Then I raised this with the council for noise pollution they sent them a letter and advised me to keep a diary of the noise, but i was lucky in one night they left but i found out later they had been working and claiming benefits at the same time.
Best way is to hound the landlord and Council till they do something