['LIVEWIRE?']

Telstar, The main (from a broadcasting point of view) between UK & NZ, is that the latter is maybe 1000 miles from any other inhabited land. I don't know how frequency allocations are/were managed in that area, perhaps Arjoll will enlighten us, but given the distance between NZ and other places, I'd imagine that co or adjacent channel interference, even by night, is less of a problem than in Europe. AFAIK no really high power MW stations in either NZ or Australia, either)