Honestly Maizie, although what you say is totally correct- I am not too worried about food, compared to other things like isotopes, medicines, energy supplies and petrol/diesel.
Food is something we can sort of adapt to- eat much simpler, much less choice, more local, sort of. Mind you, with winter coming, not much time to dig out flower beds and lawns to grow more food- but at least meat should be cheap for a while, as millions will have to be slaughtered as no feed for them, and no market to sell them. But of course, it will be the poorest who will suffer most- as for everything to do with Brexit, jobs and all.