Just a guess – WWII bomb damage between Norton & Billingham – a failed attempt to bomb ICI? From my fathers notes: The other bomb dropped nearer to our shelter. The bomb whistled on the way down. It got louder and louder and seemed to last for minutes but it would only have been for a few seconds. There was a very loud bang and the earth and shelter shook violently. We thought the bomb had dropped just outside but it was about 300 metres away. It left a huge crater a fortunately on open ground. No one was injured. (This information was kindly provided by Sarah Sheraton). Can you help?