The Strata Committee needs to send him a letter immediately inviting him to formalise postdated permission in the form of a by-law accepting responsibility for the renovations, or to reinstate common property to its previous state. This letter will go on the record and turn up in a strata search. It should also be sent to his real estate agent so they can’t deny they knew about this. Once it’s on the record, the vendor will have to do something or they will find it very difficult to sell the property.