"Zee". I'm very much convinced that with the British accent (or English accent, whatever the -blam!-) it's pronounced "zeh". It would make sense given the way sounds, letters and words are formed with that particular accent. Also, think about this; "Zehbra", "Zedbra". I've heard the former, certainly not the latter. On a similar note; it makes absolutely zero sense to me that Canadians say "Zed"...