For some reason, 1876 as an opening date is online and often repeated [including on the Silver Vaults website] but is entirely incorrect.
The building was hit by a bomb in the First World War and, as your article said, severely damaged in a raid during the Second World War, although only the upper parts of the Safe Deposit were destroyed.
The new building, designed by the firm of Richardson and Gill [Sir Albert Edward Richardson] is a much more interesting structure than its appearance currently allows.
Peter Cameron
Silver Vaults 54-57.