[addyta.org]

Just to get the preaching over - you were speeding blah, blah, blah

At that time and location, I would expect they were there to target a vehicle or vehicles that they had been receiving complaints about.
Depending on the type of hand help detector, it may have required a second vehicle to stop you and give you the ticket or it may have an inbuilt camera that would take a picture of your vehicle and the speed it was travelling at.
In either case, you may still receive a ticket in the mail but there is a time limit which you should enquire about anonomously.

The question about speeding up to overtake a slower moving vehicle is quite controversial - I am of the opinion it can be a definite neccessity - within reason.
With a 10kph difference in speed, starting 10 metres behind a 5 metre long vehicle travelling at 90 kph and pulling in 10 metres past (safe distance between vehicles), you'll need 9 seconds (plus acc'n/decc'n time) for the action, during which you'd have travelled 250 metres. Most of this would be on the wrong side of the road.
Increasing this to 110kph would halve this with the attendant reduction in exposure time.

This is the main reason I have the top end RADAR/LASER detector available in this country - a BELL XR STI [thumbup] which cost more than the car it's in. In my personal vehicles (work may expect it at times but they don't pay me enough), I generally drive at, or a little above, the posted open road speed limit and if I have to pass a slow moving vehicle I'll do it as quickly and safely as I can, however this means a possible ticket which is quite dear so the detector is cheap insurance on my part.

Something y'all should remember is that speedo and tyre tolerances mean there could be close to 10mph difference in actual road speed for the same speedo reading - so that "speed demon" trying to get past may still be driving at a speed they believe is legal, ditto the "slow coach" that's holding you up.

I'm not a professional driver, as such, but have been driving for over thirty years in a wide variety of vehicles* so have some experience on my part, as well. Traffic, vehicle, weather and road conditions will generally regulate my speed

*Licences for
Motorcycle
Car
Heavy truck and trailer to 50 tonne GVW
Wheeled special type vehicle
Tracked special type vehicle
Rollers special type vehicles
Forklift special type vehicle