Thanks for Bethnal Green Parishes map Pegleg. I've been finding some very useful old OS Maps online which help but of course Parish boundaries did chop and change over the years. Cali's cabbie could of course have had grandparents who lived in Old Nichol and family folklore does come filtering down through the generations and if he still lived in the area then continuity of memory would be preserved. (We had a family tale that great-great-great-grandfather's first wife died by being thrown from a carriage. In fact, from the various death certificates we now have, it was his second wife's mother who suffered that fate!! But, alas, not from a handsome carriage but a two wheeled cart in Greenwich)
Whilst looking at Arnold Circus I came across a fact, not sure if totally true, but the rents were too expensive for the dispossessed tenants and out of the original population only 11 were rehoused there, the accommodation going to the 'wealthier, respectable, poor' and so the others were pushed out further East into equally dire accommodation.. I suspect it was like the Peabody Estates in that you had to meet quite strict criteria to be allocated an apartments there. Of course now that Shoreditch is quite up and coming and rather chi-chi and unaffordable where do the remaining poor get moved to?