Wow - that is dissapointing. Don't know much about the redflex mobile speed cameras but you would expect an advanced warning. The the Multanovas they had in WA were 0.5 mW and with a decent detector and set to its narrow frequency band of the speed camera (wideband off) you could get a good warning on these.
This is from delonix radar website - sorry not allowed to add a link here but google is your friend. There is alot of information on there and a page dedicated to New Zealand encounters.
"They bought around 30 of Autopatrol PR100 cameras, which are a mobile Ka band unit operating on 34.6GHz +/- 150MHz at a lower power rating around 0.2 - 0.5 watts"
v1 sounds the best unit for warning. Also make sure your detector is set up for narrow Ka band and 34.6Ghz only.
Not that I have seen the escort redline seems to be the one. But the thing is because the New Zealand dollar is so weak it costs us about 1000 dollars for the Escort Redline very pricey.
The Escort 8500 X50 seems to pick up the Autopatrol very easly
Take a look at his link and scroll down to the bottom, this might be something you would want to try.
That's some weak warning. But with very weak signal comes short warning. were these one of the things that vertical mounting of the rd helped over horizontal mounting?
I have also tested many of the radar detectors against the Redflex vans when they were using them here in Arizona. What I found is that they had polarized their K band antenna vertically and used very low power. The only detector that did fairly well with the Redflex vans was the Redline and even that was pushing it.