Conor
Thank you.
Someone else says there wasn't one. It is absolutely obvious that there would have been one.
If the offence was intended to be absolute, the only defence would be on the facts of the case ("it wasn't me driving") rather than on its merits ("it was me driving but I didn't know the Kosovans were in the back"). That's the way it was supposed to work, as I understand it. A bit like driving with a bald tyre. Ignorance = no excuse.
They were impounded as well as having a £2000 fine imposed? That sounds unnecessarily harsh.
Again, AIUI, haulage has always been an industry where the little man can get in without TOO much capital, but can then struggle to stay above water unless he is lucky. There have always been lots of industry entrants and lots of leavers. Whether that changed very much during the period of those fines, I don't know. But not many businesses would go bankrupt over the loss of £2000 without other (more) aggravating factors. £2000 is no trivial sum but it certainly isn't life-changing unless it happens to be the last straw on an overburdened camel's back.