Just happen to have a copy here. Interesting story, we went to Bletchley Park a few years ago and there was an elderly lady pushing her husband around in a wheel chair. We were a group listening to a fella telling the story of the place. The old fella interrupted and said “well that’s not quite right” and went on to explain. His wife asked “how did you know that?” He said I worked here to which she replied, so did I.