29 years in first fill sherry? That does not seem credible to me. I would expect even more wood in the delivery. I suspect this whisky was first maturing in a refill sherry cask which wasn't doing much, so it was reracked into first fill to spruce it up. That's my theory but I am willing to be disabused of the notion.
sweet oak, figgy, raisins, old leather sofa, shoe polish
bitter and woody already, burnt toffee
long; dark chocolate