It follows that if the UK govt (& Brexiteers) really want to "wean the country off" low-paid migrants, pay and conditions will have to go up a lot. Robots can't square the circle (not yet). And that means food prices will have to rise. Trade-offs exist.
The UK has v cheap food, relative to similarly rich countries, so this might be a trade off you're happy to make. Some will say "it will hurt the poor, who already rely on food banks" but the problem there isn't food prices, it's inadequate floor on incomes, & housing costs.
Some more charts on food prices, because they're interesting. Which country stands out here? (HFCE is household final consumption expenditure) https://ec.europa.eu/eurostat/statistics-explained/index.php?title=File:Price_level_indices_for_food,_beverages_and_tobacco,_2019_(EU-27%3D100)_dec.png
Here, you can see the poor do spend a bigger % of their budgets on food than the rich, but for me, the elephant in the room is housing costs.
But the govt doesn't seem to be thinking about this at all. Instead it's chiding farmers for not employing more Brits, & quietly expanding a seasonal worker visa pilot to bring people in from Ukraine and Moldova. https://www.gov.uk/government/publications/seasonal-workers-pilot-request-for-information/seasonal-workers-pilot-request-for-information