So, Laphroaig - peaty, smoky, with a salty sweetness about it. Bowmore - a smoky sweetness, with a peppery then smooth aftertaste. Aberlour - really smooth, a hint of vanilla & Xmas spices (like liquid Xmas cake). Highland Park - even smoother, quite silky-smooth in fact, with hints of heather (as if it's been distilled from Fraoch Ale) & honey; superb.
So there you have it, a scientific foray in spirits. Results are inconclusive, so I'll repeat the experiment, maybe adding Glenmorangie to the test subjects, if the current floods subside enough for me to get to a shop/off-licence.