I should explain more about that rule
The original rules for pre-65 in Australia were written in the early 1990s to exclude the avalanche of affordable, economical and reliable Spanish trials bikes that started with the Bultaco M10 in 1965.
The original wording included "no Spanish Machines" as a way to stop people riding Bultacos in that class, due to a percieved performance advantage over pommy bikes.
At some time in the late 1990s or early 2000s, a Victorian enthusiast who wanted to ride his converted 1963 Campera, convinced the the MA representative for vintage trials (Chris Leighfield) of the merits of letting legit pre-65 Bultacos ride in pre-65 trials. The words "no Spanish machines" then diasppeared from the rulebook. The person wanting the rule change never did actually ride his Campera in pre-65 trials, and sadly Chris Leighfield passed away in the mid 2000s.
No-one else rode or wanted to ride a Bultaco in pre-65 for quite a few years, until Col Phillipson decided to restore an M10 (photo in VMX magazine trials column in late 2010) to a very high standard. Col thought this bike was pre-65 and his son Alan, who is a very good trials rider, rode it in the 2010 Aussie titles, and won pre-65 class on it. The eligibility of the bike was not questioned at scrutineering or during the trial, but in the weeks/months after Alan won the title, there was a big furore about whether the bike was eligible or not.
The outcome was that it was found that even though S Miller was riding a Bultaco in late 1964, the M10 did not come out until during 1965.
The rulebook was then changed back to what you see now "no Spanish machines"
I told you it was a can of worms
The pre-65 carby rule is another riveting story for another day