A couple of months ago, i went through the whole "build records from the British Motor Industry Heritage Trust" with a view to age related plate, with a view to tax exemption, etc.
I spoke, at length, with various different departments, and what i stated was what i was told.
I wont argue as to if its right or wrong, simply that, when i called the DVLA and BMIHT, that that was (my memory) of what i was told.
Id rather it were the other way, certainly, so id like to be wrong, but, as i say, its what i was told.
Its a simple matter to call the DVLA to be sure, however, as my 101 wont be 40 until next september, i, personally, wont be worrying about it too much till then! : )