Everything bobnat said, absolutely true. Though I have no idea about vendors in the UK, so take his word for it.
And unfortunately it really is just as 'hit and miss', buying flavors, as buying ejuice; there are so many brands doing the same basic flavors, and they're all kinda different... the good thing is, flavors don't cost nearly as much as finished ejuice, so it's actually
lots less costly to experiment DIY-style than buying ejuice.
One rule of thumb I heard over at Asshat Central is "50% main flavor, 50% background/supporting flavors". It doesn't have to be EXACT, but if you aim for something around that, it usually works out pretty well.
Capella's Sweet Cream is a must-have, it goes in so many different mixes, and its taste of "fresh cream" is absolutely authentic; I even put it in food! It's also diketone-free.
Welcome to the tastiest rabbit hole in vaping.
Andria