To be honest: I am neither willing to pay 450 pounds for a 21-years old that I score below 90 points nor do I think that a three points taste difference justifies a tenfold price tag. It will be interesting to watch if they really sell all the bottles for this outrageous price tag (and of course, who buys such stuff)...
The colour of the 14 is a little darker than the 21 but this is irrelevant because they use caramel to fix it. The nose of the 21 is much more complex and balanced with more subtle and delicate aromas (oils, honey, beeswax, some fruits like quinces and apricots). Actually it is pretty good compared to the rather simple and vanilla-toffee driven nose of the 14 but I would not call this excellent. I go for a 3 points advantage in favour of the 21...
The taste of the 21 is nicely layered on different honeys and barley sugars, some fruits and spices and a slight flavour of white chocolate (after some chewing). All is nicely balanced and delicate, I like this much more than the 14's taste that is simple, bold and easy quaffable but not very interesting to explore. I go for a 4 points advantage here… Water is not recommended on the 21 because this dram flattens quickly in all dimensions while the 14 rather improves on some water added (it releases more aromas and flavours and gets smoother, I like it best when reduced to about 35% abv).
The 21 arrives warming and somewhat coating in the mouth with a minor drying feeling (plastics). The finish is rather long and adds more fine chocolatey notes to the profile that I like. Again there is a slight drying-astringent feeling towards the end that reminds me of plastic notes. The finish of the 14 is of medium length only and adds more interesting flavours to the taste like spices, chocolatey notes (too) and more fruits. This is the best about the 14 and so the advantage of the 21 are a mere 2 points in this category.