Riccardo, I found this report in NSW Police Gazette, 4 Nov 1891, page 368.
Edwin Bull missing from his home, 33 Irving Street, since the 12th ultimo - Edwin Bull, 14 years of age, black hair, dark eyes, freckled face, dressed in dark coat and gray trousers.
Could this be our Edwin Massy Bull? Does the address ring any bells for you?
Cheers, Heather