From ARNIE:
Kaindub’s suggestion is a wise one – it’s quicker, less costly, and leads to largely the same outcome (i.e. you can use the space to the exclusion of others).
Our building, a block of nine in Sydney, has three different exclusive use by-laws, all for similar reasons – weird common area land that can only be used by one lot.
The procedure is relatively straightforward and provided you haven’t burned any bridges with your neighbours, they would have no reasonable grounds to object.
My starting point would be the strata managers. They’ll know what to do for your block and jurisdiction if they’re any good.
Good luck!