Ann: Resignation of CEO. Global search commenced for new CEO, page-51

This kind of business has very strong network effects and both REA and DHG are established players owning between them a huge share of the overall market, so I think barrier to entry is quite high at this stage. Note network effects work both ways - REA/DHG is where people look for properties, so that to large extent forces the agents to advertise there in order to reach wide audience. A group of agents trying to set up their own business just wouldn't cut it at this stage, without some serious disruptive idea/advantage.

My guess is if Cat was looking for a challenge building an online real estate business, he'd stay with DHG - they have plenty of challenges ahead in order to grab market share from REA, which is the incumbent after all. So unlikely scenario IMHO.