Education & Work Career Change

+1 for do it.

It sounds like you're in the perfect position to do it. You've already left your job!
I say buy a 4th IP so it puts a fire underneath you and a need to work... might motive you a little more?

It's not like you're in a job paying 200k+ that you hate and you really have to decide if you should leave.. you're halfway there.
Whilst true you may become over exposed, It's pretty much possible to become over-exposed to anything you do too much. I can't see why you wouldn't re-find your love for it if you become over exposed then left.
I'm 100% confident if things don't work out you can get a similar retail job, possibly even better with your experience.
You have NOTHING to loose.
You will probably even see more opportunities with places for sale being in the industry. Provided you do the right thing by people 100% of time, they will continue to come back.

 

Great points by Big Will!

I think best way to go would be pa to a leading agent in the area. Get a certification of registration first. You don't even need to go through job ads. Call the best local agencies in the area and speak to the directors. Directors are always on the look out for agents. It's so important to be with an established agency, great for exposure and support.