On location: Orkney

We waited by the corner of the choir and the south transept; our guide needed to fetch something. She returned with a plasticised flip-book that was full of photographs of a smiling and slightly adipose middle-aged woman striking various attitudes: standing on narrow stone spiral stairs, squeezing between ancient walls, and crouching to negotiate low and knobbly ceilings. I didn’t want to look at the photographs – but our guide insisted. “It’s for our insurance,” she explained. “We have to in...