No! trade would not cease under almost any scenario... Ascot would never be Ascot without the Champers and strawberries ..replacing it with Strongbow Cider would not be proper, nor would repairing ones Purdey shotguns in a French workshop, suita Belgian mangate... Those people will always take care of themselves, but the market for Golden Delicious might drop and be replaced by Cox's Orange Pippins. The range of cheeses available might drop on both sideseven if we leave with no deal are you seriously suggesting that trade would cease out of spite. Politicians on both sides of the channel would have to be pretty stupid (maybe they are) for that to happen
But don't be so sanguine about the common sense of political classes... As Barnum is reputed to to have said.. no one has gone broke underestimating the sense of taste of the public.