Oak, oak, oak at first in the taste. Not in an overwhelming way though. The classic grain whisky sweetness is there, but very subdued to what you normally get in old grain whisky. Burned caramel and sweet raisins. The finish is loooong and the sweetness comes a bit more forward.
46 year old might seem as a strange number, but I think they knew exactly what they were doing. I think a couple of years longer in the casks would have made this all oaky and ruined the whisky. If you like well-aged cask influenced whisky - this is you. I will give this 90/100 (22/22/23/23).