While I didn't think the current Shoreham Collection was the same collection, I nevertheless decided to contact them and ask. This morning I received this very helpful reply.
The museum you visited in 2001 was the D Day Aviation Museum which closed in 2003 to make
way for a Ricardo Engineering development, the contents of the museum were sold by auction.
So I'm glad I got to have a look around when I did, and I hope everything found a worthy home.