For decades, if not centuries, this was how the seasonal migrant labour market worked. Employers shipped in people from poorer countries temporarily. They were housed on the premises, effectively getting free, or at least highly subsidised board. They worked long hard hours for low pay but they had next to no outgoings and paid little or no tax so, as long as they kept their heads down and got on with it, they kept most of what they earned and when the season ended they went home taking their earnings with them where it would be worth many times it's UK value.
That's the whole point of migrant labour. They come from poorer countries, their employer gives them bed and board and then they go home with their money where they find themselves relatively affluent. The employer gets a stable labour source that isn't effected by economic fluctuations, his crop gets picked at low cost so UK consumers get affordable food on the shelves and the labourers themselves do well because they go home afterwards where their money inflates to many times its UK value making the drudgery well worthwhile. Everyone wins.
Before WW2 gypsies often did a lot of this work. They brought their accommodation with them and were paid cash. That was a good arrangement too. They had a stake in society, a source of legal income, safe places to camp while they worked, an incentive to have good relations with farmers and the crops got picked.
EU freedom off movement and endless tightening of employment and tax regulations has killed that. While EU migrants were able to send their money home, it was worth their while doing this work. After Brexit six million of them (twice the number we were told were ever in this country at any one time) took up permanent UK residency under Boris Johnson's EU resettlement programme. We don't have a shortage of available labour. They're all still here. But we have a shortage of willing labour because suddenly, the option of swelling their income by sending it to Poland or Romania has gone and they find they can't afford to pay UK living costs on minimum wage jobs any more than British people can, so they don't want them and we're back to square one, but with six million people to house and feed added to the population. And so the cry goes up we need more migrant labour, the Ponzi scheme grinds on, the housing crisis worsens and productivity spirals ever downwards.