I am close to completing my biography of Chapman and I can tell you that it was 518 Tottenham High Road, opposite Bruce Grove station. He rented it from thirty-five-year-old Henry James Pincott, who also owned No.520, where he ran a tobacconist shop. Chapman, or rather Kłosowski as he was then, took up residence on 7th January 1895, using the ground floor for his barbershop — under the rather grand name ‘The Criterion Toilet’ — and living upstairs.
The building was right in the epicentre of last year's riots.
Hope this helps!
Helena Wojtczak BSc (Hons) FRHistS.