The international problem was another reason for dropping letters from dials. Calling ACOrn 1234 or HOLborn 9876 from a phone within London, or within the UK was fine, but imagine the trouble it would have caused placing a direct-dialed international call to one of these exchanges from North America.
By the way, some of the very early automatic exchanges (i.e. turn of the century) in America used phones with an 11-hole dial. The extra position was marked "Long distance" and stepped the selector to an 11th level for accessing an operator.
