Have you tried Ledaig single malt from Morrisons? It's made by Tobermory and is the best £18 single malt I've ever tasted.
The first impression is of a calmer, less challenging Ardbeg, then a less firey Bowmore. But this whisky certainly doesn't lack definition, it is wonderfully light but won't reward you with the long rolling subtly changing tastes of a more expensive single malt from an island, but it certainly tastes more expensive than £18!
I once paid £180 for a bottle of whisky from the defunct Islay distillery Port Ellen; this is nicer.