Thanks, Bill. I'd heard of the Napoo in Ancoats, and at Belle Vue, in the 1920s - but not in Hulme. I'd assumed that the Napoo referred to a single gang, based somewhere round Oldham Road. But after reading your post, it sounds like there might have been separate "Napoo" gangs from different parts of Manchester. I think the word 'Napoo' comes from soldiers' slang of the First World War. My research covers the earlier period (1870-1900), so it goes a generation further back.
Best wishes,
Andy