I've made two different blends based on the pairing of North British grain whisky and Highland Park single malt, both components of Edrington's blends. The first contained only those two elements, while the second added Bunnahabhain to the mix. I finally got ahold of some Macallan and decided to see how that would influence the blend.
•17 mL Signatory North British 16 Year CS
•5 mL Highland Park 12 Year
•5 mL Highland Park 15 Year
•3 mL Macallan 12 Year
•3 mL water
North British/Highland Park/Macallan Blend
Nose: sweet grain, rich caramel, creamy vanilla, mossy peat with twigs, layers of sherry, fudge, thick malt, orange/lime peel, ham, incense, gently floral. After adding a few drops of water, the grain becomes more assertive, the sherry integrates with the peat and oak, and some seashore/shellfish notes emerge.
Taste: sweet grain with a layer of sherry on top up front, a solid undercurrent of well-integrated oak, becomes maltier in the middle with mossy peat and floral notes in the background, fades out with cotton candy and more grain. After dilution, it becomes sweeter up front and more integrated in the middle, with more peat, oak, incense, and baking spices at the back.
Finish: grain and malt, sherry residue, mossy peat, mild oak
It is perhaps unsurprising that this was more successful than the Bunnahabhain blend. Macallan and Highland Park are both owned by Edrington, which makes me suspect that they're sourcing their sherry casks from the same bodegas. Putting the two together amps up the sherry character without sidelining the peat as much as Bunnahabhain did. With that said, I don't think this is better than the blend made with Highland Park as the only malt component. This version may be more approachable, with the peat pushed somewhat into the background, but sometimes it's hard to beat the original.