I agree with Scotlandx that there should be a by law to cover such changes so that the OC isn’t left with the legacy of upkeep and repairs in the future. The EC OC should arrange a retrospective by law to cover,those already modified, and any other owners who wish to do the same, within reason.
Personally I would ask the EC why I was required to have a by law and pay for it when there isn’t a by law to cover the others. And should they go ahead with a by law be prepared for a slight wait. When we had a by law drawn up it would have taken at least 6 weeks of toing and froing, rewrite after rewrite before we got it right. The wording has to be absolutely right and applicable to the matter and the complex.
Jimmy has mentioned that the new strata law reform may include changes made to an apartment be the responsibility of the owner or any subsequent owner. So if they do not want to go down the path of a by law to cover all, them perhaps you could wait. A by law does just that, makes any change the responsibility of the owner.