KinGlassie Double Matured is a single malt Scotch whisky aged for 8 years and bottled at 46.3% ABV. For a newer whisky drinker, "double matured" usually means the spirit spent time in one cask before a further period in a second cask to add extra layers of flavour.
The Amontillado cask mention points to a finishing or secondary maturation in a sherry-seasoned cask style associated with drier, nutty and gently savoury notes. Expect a youthful single malt with added cask influence rather than the deeper complexity of a much older whisky.