The reason the H & E field is now a boating lake, is that is became a gravel pit..
I, lived in Broxbourne from 1950 to 1968 and knew several people who flew there. I also met Neville Browning later in Norfolk and clearly remember his fatal crash. The weather was a bit claggy and he wanted to give the crowd a show as the cloudbase was a bit low for most. A pilot friend was there and thought he lost it from lack of a horizon. Was the engine failure from the accident report?
DW