Rereading my original post I accept that it sounded critcal of the crew and, at the time, I will admit that I did think that (however much we SLF ignore it) they should have repeated the whole thing. I now unerstand that this not a requirement.
So now I would like to change my question.
Assuming you don't leave the original aircraft upon which the briefing was given is there a time after which it is mandatory to repeat the briefing in the case of delay? Is the period set by the operator or the country where the airline is based/controlled or the country where the delay is experienced o something else or are there no rules? I'll be honest, I'm not sure what the time limit should be but I do believe there comes a time when the briefing should be repeated.
I was on an airline recently where, before landing, a verbal reminder (not the full show) of a limited number of salient points, was given and I thought that was actually rather a good idea. After a long haul flight how many of us can remember the briefing we got all those hours ago?
And, in case anyone is wondering I do not consider myself a nervous flyer and I'm not in favour of the "Nanny State"