Sounds like kitten farming, and that ought to be reported to the local RSPCA, which you can do in confidence, I believe. We've just had PUP AID here in Stanmer Park, well supported by a lot of big names in rock 'n' pop, to help stamp out puppy farming - although, as I said before, when I approached the RSPCA about this some years ago, their response was bizarre, to say the least. That they didn't stamp it out, as they'd rather know where the farms were, than have it go underground.
What do you think these people are doing with the queens, Redhead? Killing them themselves? Or abandoning them? I can't see vets putting down healthy cats, and I'd imagine a local shelter might have suspicions by now. There are various cat rescues which might help you, but some form of action would be good.