Dear Hugh,
You might try this Hispanic Genealogy group in
California. They are a group for the Sonora, Mexico area (I think), but they might have information for who to ask or where to look regarding Mexico City's cemeteries.
familia_ancestral_research@juno.comI, too, would like that piece of information as well. My grandfather was born in Mexico City, his father was born in
Wooler, Northumberland (?), England. I don't know if my
g-grandparents died in Mexico City. Good
Luck, and reply if you find anything, Susan