“The pound has hit an all-time low,”
Because it was over-valued for some time. (See below).
“Prices in the supermarkets are rising and will continue to rise.”
Because supermarkets import much of their goods. For eight years or thereabouts the government has been printing worthless money (one of the main reasons why the pound became overvalued). If you print more pounds without any concomitant increase in underlying value then each one becomes worth less. Simple schoolboy economics. Eventually the chickens come home to roost despite the government’s best efforts at “containment”.
“A number of companies have mad plans to leave,”
But none have actually left (because Brexit has not happened). Time will tell if any of them carry out their threat.
“Perhaps you can tell us which of the promised benefits of Brexit have come to fruition?”
Apart from Messrs Cameron and Osborne sailing off into the sunset, none. And that’s because, as you pointed out, Brexit has not begun yet. It was quite obvious, and well forecast, that considerable instability would ensue from a vote to leave. Short term pain for long term gain,and all that.
“I know a number of people who voted Brexit specifically becuaws they were convinced it would save the NHS.”
Then they were idiots.