Hi Karen welcome to the community.
Have a read here and you should be able to add any photos in your thread www.rspb.org.uk/.../191572.aspx
I've found contact details but they are from 2012 but you could still try it www.rspb.org.uk/.../appeal-for-reports-of-corncrakes.aspx
Hi Karen. We were in Orkney at the start of June but didn't see or hear any Corncrakes. I believe that all sightings and/or heard birds are still of great interest to the RSPB there so I would perhaps follow Alan's link and report your sighting.