I too suggest the cats protection league, they certainly helped me with ferral cats that moved into my barn. They lent me a cage trap, they collected them as I caught them, the adults were nutered, wormed, checked against fleas and returned to me, the kittens were kept to be rehomed, all at no cost to me. Now have a male and female that cannot have any more kittens, and they are more contented with life, no more fights, and all for a few cats biscuits in the evening.
Regards Jan