What is wrong with "We are down in the cafe" down and below should be interchangeable
In the real world, "We are down in the café" would only be acceptable in context that removes any ambiguity.
⦁ "Phone upstairs to the apartment. Tell your mother we are down in the café."
⦁ "Last month's accounts show the hotel takings are average but we are down (en baja ) in the café."
⦁ "The WiFi is up again in the hotel, but we are still down (caido ) in the café."
⦁ Two wounded soldiers are radioing for help. "We are down in the café. Get that sniper so the ambulance can come in."
Also note that, although DL usually ignores punctuation, that comma is vital. "We are dowstairs in the café." and "We are downstairs, in the café." have different meanings.
As for this exercise, whether the authors intentionally made the sentence unclear or whether it was just carelessness is actually irrelevant. We have an ambiguous sentence to work with and we must handle it as we see fit. In conversation for example it would beg a request for more information --- eg, "Do you mean down the street, downstairs, down in the basement, down on the takings, etc, etc?"
Which of a range of interpretations was intended, given DL's usual practices, will not be forthcoming except in these discussions. And whether DL says our translation is "right" or "wrong" often actually means nothing at all. Let's just take the opportunity to improve our understanding of Spanish (and probably of English too) and move on.
You are right as usual, Roger, but it isn't necessary to be labor what is essentially a fairly minor point.
In the UK a cafeteria tends to be the eating place within a place of work. Cafe is the usual word used when in town.