Pleased to have helped to provide some confirmation – over the years Newark organised a variety of similar open cockpit events. Until Covid this moved onto a more regular basis with a team of volunteer cockpit openers forming part of the museum’s mainstream offer. You can glean a few more details in here. 
http://www.newarkairmuseum.org/NAM_open_cockpits

Picking up on another thread and perhaps someone who participated in that visit before Christmas I was in contact with JDK who pointed me in the direction to help save the Warbirds Worldwide Archive material.
http://www.newarkairmuseum.org/Warbirds_Worldwide_Archive