Bend over backwards
You are sensible to want to be well informed about health and safety. Your first port of call should be a web search. I turned up a number of sites with a search of "PE and health safety". "Gymnastics" or "primary" would further refine the search and tailor it more to your needs. Many local authorities have produced policy documents to cover health and safety and can be found on the web. Check your school's policy to see if it needs updating. There is a risk that you might be given responsibility for your school's general health and safety policy, and not just gymnastics, if you show too much interest. It is questionable whether such a responsibility would qualify for a teaching and learning repsonsibility payment under the new system, especially if part of the responsibility was for areas not related to teaching and learning.