Left wing of Albert Hall Museum

Has anyone who has been to the Albert Hall Museum confirmed that the left wing of the level one is not accessible to public? We went this morning and started from the right wing when we entered, it led us to the 2nd floor and there’s no turning back to the 1st floor exhibition hall except to the Exit. We asked a few securities, they asked us to head to exit and enter again but when we tried to do so, the security at the front gate told us that we’ve seen everything and the left wing is a restricted area? I remember clearly that there were people roaming there.