They are a cask storage service, buy/sell and bottle casks. The Dalmore was vatted from 4 oloroso octaves.
I've not had a bad one yet, tried 7 different bottles so far. I ordered the Dalmore and Aultmore yesterday, time will tell if it keeps up that record.
Another decent bottler is Chorlton Whisky. He's got a couple of releases coming soon. Charges about a tenner more than Whisky Broker, and they tend to go fast as well, especially any Islay releases.
https://chorltonwhisky.co.uk/uncategorized/chorlton-whisky-bottlings-3/