Fair Trading are right up to a point … but it doesn’t apply here. Perhaps you should park your car in that spot and see what happens. If they say you aren’t allowed to park there, then they are claiming exclusive use of the common property which, you are right, does require a 75 percent vote.
At the very least they are obstructing common property which no amount of cosy votes at the EC will allow them to do.
So here is my suggestion:
In the interest of future good relations with your neighbours, ask for a meeting to resolve this amicably. Let them be the first to talk about their “rights”.
If they are unreceptive, you can argue that they are claiming exclusive use (which they are not entitled to do) and that they are obstructing common property (ditto).
If the problem continues, talk to an experienced strata lawyer (like our sponsors Makinson d’Apice – or others) about sending them a letter explaining that you would prefer to settle this amicably but setting out what your options are should they fail to agree (everything from a CTTT order to the appointment of a strata manager).
After that, your lawyers will advise you on the next step. You can pursue this yourself through Fair Trading but in the interest of good relations in what is a small community, I would escalate this slowly rather than going for ‘shock and awe’ in the first instance.