Hi. I'm new here so apologies if this is in te wrong area. I have a 1/4oz gold £25 bullion. In box with two whiskey miniatures and certificate. It was one in a famous grouse competition in the 80s. Looking to get a value for the coin! Phoned a place called scot mint who offered me £200 for it, does that mean the coin in worth round about £400? Any help getting a value would be greatly appreciated