So this is either a case of batch variation or of some serious oxidization. I've had this one before and remember it as much "darker" and more Oloroso-influenced. The sample I'm working with here is considerably brighter, fruitier, and lighter.
Still very solid, though, and the only core-range Glenmo I'd consider buying again.
UPDATE: Having recently opened a bottle of my own, my suspicion is confirmed: the sample I had was a bit weak (perhaps from the last third of an open bottle, something like that). This is much better - darker, stronger, more to the point - and I'm raising my overall score from 84 to 86.
Grassy, floral, fruity. Pineapple, peaches and hay. Marzipan, white chocolate, vanilla. Seems younger than 18 initially. But wait: after some time, the wood begins to make its presence felt on the nose as well. Really hits its stride once it has wet the gullet. After the first sips, a herbal / spicy component kicks in that is highly reminiscent of some good-quality European-oak ex-sherry casks.
Ah, here's where the age comes through. Immediate oak presence with creamy tannins and a good body for the strength. Plenty of Oloroso / umami flavors. Sweet, spicy and luscious, with enough substance to serve as an after-dinner dram. The Glenmo fruits are present, but they're counterbalanced by a nicely measured tannic bitterness. There may be some (small measure of) European oak in here after all.
Medium length, with a nice, slow fade, mainly on fruit and pepper. Seems more like 46 than 43 percent, which doesn't happen to often. A bit fizzy, with acidity and bitterness playing off each other. The sweetness recedes quite a bit at this point. Nothing crazy special, but also nothing unpleasant.