Can recommend this one Rob.
http://www.speedcameradefence.com/shop/viewdetails.asp?productID=20
Basically, you don't want a radar detector, you want a laser Jammer.
Not sure your wish list - but a quick run down is as follows:
Gatso's - Radar detector required
Tripods/Guns = Laser Jammer required.
Most police have changed their old guns to new Laser ones which are more reliable and accurate. ( used to use Radar).
However, in many cases by the time you get the alert, the Gatso has you already as they ahve a fair distance/reach.
LAser Jammers work by actually blocking the signal which gives a standard error reading on the gun/tripod. They then have to re-aim to get a nother reading.
The jammer audibly warns you when it is Jamming and you slow down then switch off when nearer the speed limit. If you leave it on it will continuously block any reading.
This is prob the best in radar detector with best range/reviews.
http://www.speedcameradefence.com/shop/viewdetails.asp?productID=8
A Mate uses both of these and has been saved a few times shall we say...
Expensive, but they work.