Sir Humphrey is suggesrib8two different approaches
Th e first is to have an exclusive use by law passed
The second is to acquire the land in question.
The first option is the cheapest and simplest. You may be able to acquire the use of the land for no consideration, or the strata may ask for a yearly rental.
The second option requires valuation of the land, a new strata plan and a payment to the strata for the value of the land you acquire.
Because in both cases you are enhancing the value of your lot, the other owners are entitled to a share .
You will need legal advice in both cases, and you are likely to have to pay the OC costs as well.
Make sure the value of what you are acquiring exceeds the costs, unless of course this is a vanity purchase