I saw that too Oopsminty, which puzzles me. Presumably the agrifund knows what it's doing and thinks it can get staff from somewhere. I read somewhere that agencies will still be able to employ foreign workers, but I can't find anything about it now. If that's true, the agencies will still be able to pay pittance wages to seasonal workers. The holding company will presumably be registered overseas, so will probably escape British tax.
I've been reading about the probable future of British farming. The general prediction is that small farms won't be sustainable, so will sell out to big agrifunds, which will probably mean that out farms are owned directly or indirectly by Chinese or American investors. I hope I'm wrong.