The last rum from Guyana I had was also a single cask offering from the Scotch Malt Whisky Society ("SMWS"), which occasionally has other spirits on offer, like gin or rum or rye or Armagnac.
This is an 18 year old rum, which is easily the oldest I've ever had, from Demerara Distillers Ltd., which continues to use 200+ year old wooden stills to make their rum. It's bottled at 60.9% ABV, which is astonishing for 18 years in the barrel in, presumably, a tropical climate.

