I've seen and heard Crossbills plenty, mainly in the New Forest in southern England. Always way up high, somewhere to be glimpsed, but not photographed. On one visit to Norway, in a woodland hide I saw a strange grey bird. Not a Nuthatch - the only other grey bird seen at that hide. I got the camera on it, but it flew off before I could ID through the view finder. Checking the photos, it was a female crossbill! The first one seen at this hide.