Hello! First of all (as a Cabin Pressure & Sherlock fan): Your Tumblr is absolutely brilliant!! Second (as an admin of a Cabin Pressure Facebook page): The "otters who look like BC" thing – did you have Cabin Pressure & Ottery St. Mary in mind, when you started this? Ppl. are sometimes wondering on the Facebook page.
In fact, the original inspiration for OWLLBC came from seeing this picture, which was when I first realized that otters have an aptitude for sitting or lying with their paws pressed together in a very Sherlocky way. All the subsequent otter/Cumberbatch resemblance jokes sprang from this quirk of nature. However, I was already a Cabin Pressure fan by that point, so the fact that CP already provided a connection between Benedict and otters acted as an encouragement to pursue the joke, even though it wasn’t its origin.