It's unusual for me to disagree with you, Rob, but London Zoo had only two species of cassowary in 1988, single-wattled cassowary and Bennett's cassowary (dwarf cassowary); both were kept in the old Stork & Ostrich House.I've seen all three, and I think all three in the same collection, London in 1988
However there were also double-wattled cassowary at Whipsnade in 1988.