YES!!!! I did one in the early 90s in Kielder - 6 inches of snow on the ground, -15 at night. We hopelessly overestimated our ability to cover distance and ended up with a comically large negative score for late arrival. The lovely organisers were very understanding.
Derek Purdy (author of the original MTB guides for the Northeast) was father of one of my best friends. His quote on riding it was epic: 'Why it was magic, my head froze to the side of the tent!' (All delivered in his inimitable Northumbrian accent).