Is the Hilton Diamond status benefit a one time thing, or something you can request each year you retain GGL status?
It can be renewed. Worth keeping a close eye on the date as I think BA send a list to Hilton monthly. It is possible to drop from Diamond for a short period, with all the misery that entails! It happened to me once and the staff at the (now demolished) Basel Hilton took some pleasure in denying me lounge access by applying 'Ze rules".