Glyn, I looked into the accuracy of vans when I thought I'd been caught a couple of years back, there's loads of useful information and knowledgable people on www.ukspeedtraps.co.uk
Seems the laser cameras in the vans are pretty accurate but more importantly, they've got a range of something like 400m - which basically means they're like snipers and they pick you off before you even see them.

R U Sure
 

The van you passed was a "safety camera" van. i.e. speed camera.
There are an increasing number of vans with NPR number plate recognition cameras in the back. All these are doing is checking for crims on the move, untaxed vehicles etc.
Sometimes there will be a little sign saying what they are doing, e.g. checking for tax.
I could launch into my usual tirade about the job creation schemes surround road tax collection and enforement when the govt could could just put on the price of fuel, but I won't
:mad:
Ray

as you say they get you at a hell of a long way away.
and you only need to be a few mph over the limit to get caught.
i think ive always been a safe driver i do below 20mph in the built up areas with parked cars etc. but when a road looks safe i am inclined to go a bit over the limit.
e.g there's a dual carridge way near me that runs through an indutrial est on one side theres two juntions onthe other only one also good visability all round. it's a 40mph limit!!
i know its not up to me to decide speed limits but i must admit i used to speed along there.
i know alot of people who are on six points ( half way to a ban) that i consider v.safe consideratee drivers.
so whats the solution,the only way to not get caught is to not speed(might as well flog the bike then) or put on false plates and become a real criminal.
my rant for the day.