St. Vincent’s Hall, Grantham. Private House This was the operations room where the Dambusters' Raid was controlled from. It was a building alongside the house but was demolished after WWII. The site has been investigated by a local archaeology group but there is nothing to indicate there was anything underground.
Public visits were permitted in 2013 and were reported on by the BBC.
There was a recent planning application for a swimming pool that includes a plan of the area.