PRICE Treatise on locks ... mentions in Ch2 that he saw a large [armada] chest in the Bank of Scotland [HQ, Edinburgh]. This chest, which I think was the coffer of the Darien Company, is now in the Royal Museum of Scotland, where it may be freely and closely examined. The lid is now detached, and fixed above it.
It was in the entrance to the RBS HQ on the Mound, until that building closed for an extensive refurbishment several years ago.