Do you have any experience in estate agency? It can be a wonderful job, but it isn't for everyone.
As eequals says, the property market is stumbling. If the market crashes, and there is an extremely high probability it will, estate agents are going to be in for a very difficult few years.
Countrywide, the largest agency group have recently announced that they are closing branches and that transaction volumes are down. They are actively involved in franchising and if I were considering going this route at present, then I would be inclined to look at their offer (Bairstow Eves) first, because they have huge experience and resources to back up franchisees. But, if they are cutting back, it kind of begs the question as to why they would encourage a franchisee to extend themselves right now.
I was an estate agent for ten years, long ago, before I got into Internet development, and I must admit I have been toying with the idea of setting up an estate agency office. My thoughts at the moment are to wait a couple of years and see whether an office comes on the market as distress sale in a location that would suit me.