You're a church member who would like to get involved in helping your local school, perhaps supporting the Scripture Union group or in the 101 other ways suggested in the Serve Your Local School website (insert URL).
Almost certainly, you'll need to go through a PVG check. Don't worry, this is entirely standard. Once a school has accepted you as a potential helper, they'll handle all the paperwork (and pay the fee too!) From the school's perspective it's entirely routine: quite simply, parents need to be confident that when their children go off to school in the morning, they will be properly cared for in a safe environment. It's right that schools should make the normal checks, and 100s do so across Scotland every term.
For an excellent guide to the PVG process, go to http://www.syls.org.uk/get-started/child-protection-pvg.htmlprotection-pvg.html