Diageo's archive department (they hold the records of James Buchanan & Co. Ltd., as well as the company’s historic bottle collection) has dated your bottle from the late 1960s. They couldn't see it very clearly in the image (not sure if it has faded), but there should be a gold Royal Crest at the top of the label on the front of the bottle. Also, below this there should be a statement to say that Buchanan’s are whisky suppliers ‘by appointment’ to HM The Queen. This is a reference to the current Queen, who was first granted this Royal Warrant in 1955. The labels on your bottle are in keeping with those in their collection that were designed and first used on the Black & White bottle in 1965-1966. Therefore, your bottle will have been produced sometime between 1965 and 1970, when the style of the labeling was redesigned again.