Síle gave me “Dent’s Modern Tribes” for Christmas which investigates modern working slang and codes.
One was the army’s use of “Mess” for a place where food is served.
Dent explains that “Mess” originally meant any food, as in the Scottish; “going for the messages” when going shopping- as indeed we use the same expression in Irish/ English.
This in turn made me wonder about the French “Entremets” for dessert and yes indeed I discovered from my “Larousse Etymologique” that food put on a table was known as “Mets” and sure enough when I dip into the OED Shorter there is “Mettre”; ” to place”, given as the root of “Mess”.

Somewhere in the back of the old brain lurks the expression “A mess of pottage” which perhaps wasn’t such an awful thing after all, most likely it was simply a dish of fresh vegetables from the “Potager” or vegetable garden.