My date has a peanut allergy. Do you serve or have peanuts anywhere in house?
Not to my knowledge.suggest call to determine first hand.
Recommend you speak with the owner who by the way is a Brit.
Agree with Bronia's answer. Would pretty much assume that most restaurants in Mexico city have some sort of contact with nuts. There are some (Pujol, and perhaps others) that could give you a definitive no, but I'd play it safe with anything but a Michelin-level experience in the DF.
Get quick answers from Sir Winston Churchill's staff and past visitors.