The correct answer to this question is "1905".
To quote the official website of the run itself: "The annual event today attracts over 400 automobiles with an eligibility criteria that requires the cars to be of three or four wheel design and certified that their build took place prior to the 1 January 1905."
Admittedly this was allowed for in the leeway; but it's still a bit unfair on anyone that answered 1906 – or, indeed, 1907. And in any case, setters have a responsibility to ensure that the answers they give are correct.
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