I did some research on laser detectors / jammers a couple of years ago after losing my licence in Australia (one speeding ticket: 39 in a 30mph zone, zero tolerance area). I don't have an Australia licence to lose, but I wouldn't have been able to drive for 3 months if I did.
As was mentioned earlier, the radar detecting equipment is pointless, as the UK police are largely only using laser to collect their stealth tax. Then my understanding is that laser detection is nearly pointless, since by the time it's hit your car, and your gismo flashes, your speed has already been beamed back to the speed detection unit. All it is telling you is that you just got caught.
As for jammers, pretty sure these are illegal in (at least) the UK. You can get in A LOT more trouble for using them than just a speeding ticket... so I would strongly advise against these.
http://www.yorkpress.co.uk/news/15073866.Man_who_used_laser_to_jam_speed_camera_appears_in_court/
I use the
free TomTom app that creates a watermark over the top of my Google maps. It tells me what my GPS speed is, what the speed limit is, and flashes for fixed and reported mobile cameras, and warns me of jammed traffic ahead (very useful if you're at motorway speeds and will need to brake hard shortly). It also starts automatically when my phone connect to my car bluetooth.