There are formal training courses run by some of the big organisations such as FPA and LPC.
I dont know about formal courses but I have trained the staff of several clients to do this to the satisfaction of their insurance companies. And thats what counts in the final analysis.
The beauty of this is that it is bespoke hands on training on the clients site to cover their specific equipment, pumps, control gear, test facilities, fire alarm interfaces, interactions with other equipment such as roof vents, and can include audits of other sprinkler related topics such as monitoring the risk category and storage arrangements , maintenance of flues in high bay racking etc. Their system, their building, and controlling their hazards. You dont get that in a classroom in some swanky training centre. Give me a call anytime if you wish to discuss further.