I saw one of the Derbyshire Filth's "stealth speed vans" on the Snake a few months back. It was an old battered looking blue builders van parked untidily in a tiny pull-in spot. Only reason I spotted it was coz I was in a line of already slow moving traffic.
Insurance is a problem mind...
I thought you got automatically disqualified these days if you got caught doing a ton, or is that just an urban myth?