In this case I think there is another way of dealing with it.
“Legal right” is a blanket phrase that blurs the real issue here. The issue is that you want to do works to the unit, and you are trying to do the right thing, but the OC isn’t coming to the party. I am not sure what they mean by needing another response for you to go ahead – a by-law needs to be approved by the owners at a general meeting.
Tell the strata manager you request that an EGM be held to consider the proposal and the by-law, and you will pay for it. If they refuse, then I suggest you proceed as outlined by Jimmy.