Just been observing some of your posts Mr tiler. I think you should put invoices, advertising etc on the back burner for a bit. Not trying to discourage you at all. But learn to walk before you Leap out of the starting blocks and start sprinting. A bad job will bite you in the backside ten fold. You want to be a tiler? A good one. Then learn learn learn.
I describe us as artists. We're a finishing trade. To do it professionally i don't think you can just go out and start doing it self employed. You also need to learn how to run a business.
These short courses teach you nothing more than the concept.
I think personally id want to know exactly what im doing before i start taking peoples hard earned money.