@Boken-Lin Do you ever have one of those days when systems seem to be conspiring against you? :-(
It seems that I was totally mistaken about daylight savings not being honoured for Auckland/Wellington time zone. I have just tried again setting it via Console under Chrome and the date and time appear to be correct now. My only excuse is probably trying to do too many things simultaneously and loosing track with where I was - I apologise for wasting any of your time.
However, timezone setting using console under Firefox is still doing nothing and I have no explanation yet for this. But don't spend too much time on it - it is low priority from my perspective
Thanks again for your time