Question 5.5 from the second paper of 2010 asked for non-cardiac and non-respiratory causes of cyanosis. The following list was concocted using Walker's chapter ("Cyanosis.") in the third edition of Clinical Methods: The History, Physical, and Laboratory Examinations.
And, the causes suggested by the college in their model answer:
Nagel, Ronald L., et al. "Hemoglobin Beth Israel: A mutant causing clinically apparent cyanosis." New England Journal of Medicine 295.3 (1976): 125-130.
Walker, H. Kenneth, et al. "Cyanosis." in Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition (1990).