When we had an analogous situation, our EC let the selling real estate agent know that the owners had been issued with a ‘rules infringement notice’ re the unauthorised enclosure of common property (‘notice to comply’, I think, in NSW-speak). We had not yet reached the point of taking that on to the Tribunal before the unit was put on the market. The selling real estate agent was very diligent to let the more serious prospective purchasers know that the relevant unapproved fence had to come down and to make it clear where the boundaries were and the sorts of boundary treatments that were approvable under our rules. The new owners promptly fixed things up on moving in.