The Renniks Australian Coin and Banknote Guide 1965 says: "The Sydney Mint struck gold Two Pound and Five Pound Gold Pieces for the years 1887, 1893 and 1902. No mintage figures are available for these Pieces, however at least fourteen 1887 Gold Pieces have been estimated to exist."
According to the Catalogue of British Commonwealth Coins 1649 - 1971, "Probably not more than a dozen or so of each of the listed two and five pound gold coins [Sydney 1887, 1893, 1902] were issued".
Sydney Mint Five Pounds of 1893 not listed in Krause or Spink.
Regarding the Royal Mint London coins, Spink says in a footnote: "Beware recent forgeries".