http://www.abernethy.org.uk/

For over forty years, our four Christian Adventure Centres in Scotland have been providing a huge range of options to all kinds of people, from schools and colleges through to churches, youth groups, families and individuals.

Abernethy is a Christian run organisation - what does that mean?
Abernethy was set up to provide people of all ages with the opportunity to experience the beauty and challenge of the outdoors within a healthy Christian environment. Each member of staff is a committed Christian - we hope that our beliefs will be reflected in the way that you and your group are cared for during your stay. The "Time Out" session each evening explores the relevance of the Christian faith today and is presented in a fun, informal way. LEARN MORE

You have to dig a bit to the FAQ's to find that second quote. But the School certainly should have done that.

Nothing about police checks on staff that I can see. People I don't know having 24 hour access to my kids would worry me as much as the religion. But like you I would be assuming the School had checked all this when they recommended the centre.

By the way I don't think you are over reacting. I would be really annoyed if my kids school had pulled a stunt like this.

Michael