First tried this cheese at Inopia, a neighbourhood tapas bar in Barcelona owned by Albert Adria, Ferran's brother (it has also featured on the menu at El Bulli). Instantly fell in love with it - it's gooey, robust and deliciously moreish eaten either on its own or with some bread.
Am delighted to find that it is now available in London. I bought a round (they are small to medium sized) from Pomona deli in Belsize Park. They are getting them from Brindisa so I assume that they are available at the shop in Borough Market. Not cheap (£8.99, possibly cheaper at Brindisa shop) but better even than Vacherin Mont d'Or IMO.
Here's a link to the cheesemaker's website (Spanish language only):