You should probably have sought some sort of approval under that standard strata laws on renovations that were in force at that time.
Having missed that boat, the most you can do now is offer to take ongoing responsibility, for yourself and future owners of your lot, through a special resolution under terms that are mutually agreeable.
Or, if there have been no problems evident thus far, you are probably OK just to keep quiet.
However, some future potential purchaser, if they do a thorough strata search, might see there have been unapproved renovations and use that as leverage to lower the purchase price.
Your call.