Hi Gordon,
AS discussed, most meteorite specimens in the NHM are not on public display because they need to be maintained under controlled conditions of temperature and humidity. Also they are able to store their most valuable specimens in a dedicated lab facility with a controlled atmosphere, such as the Winchcombe meteorite. A nice example is on display:
https://britastro.org/observations/observation.php?id=20210612_184807_7b10976de4db0fd7
I visited The Vault last year and it is disappointing that few meteorites are available for public viewing.
Alex.
