Looking further at the nitty gritty of dwscrimshaw's serial Excel data, there are three Equipes ( 32231, 32239 and 32319) that presently date in his present prediction to late c.1967. Difficult to accept c.1967 even if these were several of the first Equipes ever produded, as we have good evidence from catalogues and Kilgariff's writing that first year for the Equipe model was 1969.
Dave also gives reference source to all the recorded serial data. For example, 32331 is from Retrobike thread in which original owner states purchased in '70 or "71:
http://www.retrobike.co.uk/forum/viewtopic.php?f=47&t=352729
Also he has a later Equipe 36309 predicting to 1971 in apparent original kit and yet has a campagnolo hub nut dated 1972:
https://www.bikeforums.net/classic-vintage/1140913-holdsworth-project.html
As stated by Dave, "Model Recognition Points & Years of Manufacture Plus any Documentation Should Take Precedent over These Predictions."
Thus, considering above appears more accurate to date Equipe 33612 as c.1970.
I'm sure at some point prediction will get a tweaking. Did original owner recollect year of purchase?