Hi mate. If your nearer to Essex I would say go to goldtrowel. I know Andy personally and think he's the best at the game. If you were up north I would say Andy Robinson as I've heard good things about him.
At goldtrowel you can also learn micro cement and matallics and lots of different venetian finishes.
As far as closed shop I would agree with you to a degree. As it's a high end high price line of work companies who manufacture products don't want their gear being applied in a poor way. They want you to know what your doing that's why some won't sell unless you have done a course with them. It's understandable when their reputation is on the line. I would say you don't need to be a plasterer to learn this. The first thing when teaching a plasterer to do Venetian is to knock the plastering motion out of them. It's easier to do with someone who hasn't held a trowel. That said, there are benefits to already being in the trade and to knowing about substrates and materials. I used to teach some time ago and the best people to learn were female decorators. I found most of them were very neat and clean and tidy and once they learned how to hold a trowel the rest was quite simple. I'm not saying that the majority of blokes who spread are messy or untidy but it's quite common across the trade.
I do disagree about it being old hat. It's still increasingly popular for restaurants and bars renovation and builds etc. Also anywhere that a design team or architect is involved such as private new builds for high end markets. I'd say if you like it and if nothing else you put it in your own gaff then a course would be worthwhile
