What you have to remember is motor car engineering is a moving thing. Practices that were common in the early days of motoring, supposedly obsolete in 1914 (my Motor handbook of 1914 says so...) were in fact still being done in 1930 when my three wheeler was made. However, I doubt anything made after 1946 would have them. So there is a good chance, a tester picked at random has never seen anything like the old car presented. Things like that were the justification behind the 1960 date for exemption we currently have.
But a rolling 40 years is un autre bouilloire de poisson...
I don't think other than the severely tight fisted object to paying for a yearly inspection, but when the 'expert' has never met the feature, is wrong, sometimes dangerously so, the matter does need consideration. My nearest centre that tests old cars properly and knows the engineering is 15 miles away, and I'm in St Albans (I accept there might be one nearer in London, but the advisability of going through that traffic for a test is very suspect).
Something needs to be done, but the proposal is daft. The more people who fill it out honestly should reveal that, but you do need to be a bit clever as the whole thing is slanted to get the answers they want by asking only the questions that lead to those answers.
Hopefully they get lots of answers, the one question they should have asked - but don't is what year or years are your cars? It'll never be proven, but I suspect they'll get very few answers from owners of 1930 or earlier cars, and most of the respondents will either be speaking from the sidelines, or have in my view, a relatively modern car that is either 40 years old or soon will be.
So please, whatever your views - if you've not yet done the questionnaire, please do!