Whisper, you're a bad man for stirring the sandpit
IF, we did have some sort of test/inspection. It would be farmed out to some third party contractor to administer, Capita?. They would be able to sell on your records to 3rd parties as do DVLA.
The price would not reflect the the actual value of the certification. It's a very small market compared to cars, so the revenue to support the admin infrastructure has to be divided amongst the small number of participants i.e. it would cost a fortune, Capita have to make a profit don't you know old boy.
The price would rise year on year above inflation. It would be subject to VAT i.e. it's just another tax really & got phuq all to do with safety.
It would be impossible to enforce, who's going to do that, the police? Don't make me laugh.
In order to enforce the certification, your boat would have to be registered & carry a registration number as on the Continent = more paper work & cost. I'm sure Capita would be able to find another way to make money out of that one.
Only the law abiding types would comply, as per usual, so the numpties would just ignore it, which defeats the whole point of the exercise, as it's the numpties that created the (ill)perceived need in the first place.