due to my working hours, anytime I call DLP (either the main French guest services number, or the dining reservation number) I usually call around 8.15am UK time, or just before 4pm UK time, midweek. I don't recall ever having to hold for longer than about 5 minutes at those times

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Having said that, anything over about 5 minutes is my limit for holding anyway, if I don't get to speak to an actual human being within that time I just hang up and try again later.