Car insurance - black box

Anyone know much about the workings of the telematics boxes? My lad has one fitted on his motor and yesterday he got a letter threatening to cancel his policy as, according to the black box, he'd clocked 43 in a 30 zone on a Tuesday afternoon, just up the road from our house. This seemed odd for two reasons 1. He's very conscious of his speed, mainly due to the fecking black box and 2. He was at work at the time, 20 miles away without his car...

This is because his car was taken on a low loader to be repaired on the day in question. Is it feasible that it was the low-loader that was doing 43 with the car on the back and the black box recorded it as the car itself doing 43? If that's the case he should be able to provide evidence to get this wiped off his record as it affects his premium shouldn't he?