Live in Dunedin, and for some reason my digital reception has gone...
Keep getting notice about no signal flashing on my screen.
I've had freeview for 4 years.

Have you checked the antenna / dish. Did it go out of alaignment? Has something happened to the cable that comes from the dish to your receiver?

Indoor or outdoor antenna? Have you checked the lines? Are you using a set top box for freeview? Or are you using a built-in tuner?

Do you have any other TVs in the home? Are they working? Are they on the same antenna? If not, try swapping antennas.