Yeh they can be pretty expensive, the barrel aged ones can be near the £12-15 mark (for a 330cl can!). But they are a treat (and a lot of work and time goes into producing them). I'm in Cheltenham, we have one of the best bottle shops in the country Favourite Beers The owner is a big fan of strong dark beers so they have plenty of this sort of thing. I have also bought online a fair few times last year too. My go places were Rad Beer, Premier Hop, Little Leeds Beerhouse......and a few others. Normally if you goggle the name of a beer, the shops that have it come up normally.