I am trying to find the value of a bottle of Martin's Fine & Rare Blended Scotch Whiskey (20 year) which was bottled on 2-1-40. It is 4/5 quart - 86.8 proof blended and bottled in Scotland.

It is unopened in the original box (date label is over cap) and in near perfect condition. The box does show some wear on the corners.

Can anyone recommend a potential sales price or the best place to sell this?