Speed detector 1950's

I was going through some old photos and came across this one. A New Zealand Mk 1 Ford Zephyr police car sporting a Government number plate in use from 1951 to 1955. I remember the huge black police radar detectors which were still in use in the 70's. They were a bit of a give away as they could be seen from a great distance.
Today we had lovely sunny weather. I managed to get some gardening and car cleaning done.