Having being in the same boat recently – MOT expired while i was working abroad for a couple of months and I got pulled when I drove back to the UK.
– A polite chat
– £100 fixed penalty
– no points and its not considered a ‘criminal’ offence so doesn’t show up on things like enhanced disclosures if you have to do them
They’ll let you drive home on the understanding you’re going straight home (or to a booked MOT test) and if you happened to pass another rozzer in a reasonable time frame on the same day they should give you benefit of the doubt.
I’m very surprised the offending “van” wasn’t pulled as its probably passed loads of police cars due to where it drives a lot
I think the cops needs to be actively checking plates and they also need to then be in a position to apprehend you if they get the bleep. In moving traffic a passing car will be out of sight before the APNR has time to bleep I’d imagine. In my case they’d sat themselves in a rush hour queue for traffic lights so that there was time to check the vehicles going by and to stop them. Just passing a police car isn’t likely to trigger anything if checking plates isn’t what they’re engaged in at that time.