Further to the secret filming by Salvage Hunters in 2021, we can reveal that the classic car in question was a Lotus Esprit.
Unsurprisingly really, because the first Lotus project based by Colin Chapman at Ketteringham Hall was the Esprit development programme.
Follow this link for the story:
https://www.youtube.com/watch?v=W9ZjdtBTvhk&ab_channel=QuestTV
Subsequent to the Esprit development programme, Ketteringham Hall became the base for the Lotus F1 team. The existing Hall of Fame corridor is testament to the Grand Prix winning Lotus F1 cars which were designed, constructed and operated from the Hall, throughout the 1970s and 1980s.