St. Mango's, also known as St. Manga's, appears to be some sort of Wizarding rehabilitation facility. It appears to be a typo of St. Mungo's from Harry Potter.
Role in the story[]
Voldemortserum addiction - although Proffesor Sinister refused to go get treatment. St. Mango's also treats "pedofiles". At one point, there are plans to send Snap and Loopin there after they videotape Enoby in the bath.
It seems Tara assumed the wizarding prison was St. Mangos, rather than Abkhazian, hence why Snap and Loopin were going there, but later became aware it was a medical institution.