I think real understanding of cause and effect would confirm that NYC gun regs have little to do with any crime reduction and the drop in crime rates have much more to do with policing policies and practices. Don't have to look hard....the reduction and it's cause have been widely celebrated and copied with similar effect. And which way is London's crime rates going? Yes, they have historically been lower than NYC and we know NYC's have dropped precipitously over the last 3 decades but what's happening in London. I don't think it's staying static and I don't think it's dropping.
Can't speak for Australia and NZ but Canada's escape from British direct rule had a lot more to do with Britain looking to get out of the responsibility than any methodical "escape" that soon to be Canadians planned.
Glib responses like "much like London", 'thinking death is a bad thing" or "amicable way they made their escape" rarely reveal the truth.