@Teaceratops @krans @stonebear2 @DamonHD it is most definitely possible to take the train from Vancouver from Montreal, just takes 4 days.
I would suspect that New Zealand is harder to leave than Australia. And the health treaties may be worse (or better) for UK citizens --- I don't know.
It has to be a boat, which basically seems to mean a cruise ship these days. (Another thing about cargo vessels is that they don't have doctors, so probably not actually an option even if it were possible to get a ticket).