In 1984, the Royal Mint issued a three-coin gold proof set, which consisted of the five pounds, sovereign, and half sovereign, but with no two pound coin. This was the only year for which this configuration was issued. So a proof version of the 1984 gold five pound coin exists, but only as part of, or split from, the 3-coin proof set, but in 1984, for the first time, the Mint issued a so called 'Brilliant Uncirculated' version. The 'BU' version has a letter U in a circle to the left of the date