Ziggy – How long has the a/c been in place?
If the a/c was placed on common property many years ago, and was known about, and yet nothing was ever done by the body corporate to remedy the situation then the body corporate could now face the issue of acquiescence.
You may need to check the records to make sure that no letters were ever sent to the owner who installed the a/c requesting that the a/c be removed.
The principle of acquiescence essentially denies a person (or body corporate) the right to later object to something that has in fact been in place for some time without any action or complaint having been taken by them, giving rise to an inference of assent.
It could be argued that the Body Corporate did not take steps in a reasonable time to require the removal of the air conditioning.
If this argument is able to be sustained, it may be harsh and unfair to subsequently require the removal. Reasonableness is decided objectively, based on the circumstances.