Hey Heather - do you mean Radio NZ Concert FM on your TV? You can get it in Wairarapa via satellite, but there's an additional transmission fee (payable to the transmission provider) for Radio NZ to broadcast to some areas via the digital terrestrial network (the one where signals are picked up via a UHF aerial).  That additional fee & perhaps the lack of awareness of an existing demand for their content (through the digital terrestrial platform) could be a reason why they're not in that area - but I'm just speculating here as to their reasons...might be better to ask them directly (and that way they'll also know that you're very much interested in getting Radio NZ Concert through your Freeview|HD TV - 2 birds, 1 stone as it were).

:) hope that helps! - bel