This comes into the same bracket as banning hot cross buns, or toy pigs, or advent calendars, or calling christmas winter break and a raft of other daftness, which only succeeds in alienating the average citizen from his islamic neighbours. I'm sure something like this could be taken on a one-to-one politeness level. ("Does this bother you? Yes it does a bit. Ok I'll take it elsewhere if its a problem.. etc") Forcing people to do it will simply breed resentment. (Already I have the urge to eat great amounts near a mosque, just on principle.) Ramadan is a muslim festival, celebrated by muslims. It should not be forced upon people who are not.
The reason people take working lunches is because they have work to do that they wish to complete. In our overworked NHS, this is probably the last thing they need.
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"There is a time when the operation of the machine becomes so odious, makes you so sick at heart,
that you can't take part" [Mario Savo, 1964]