Bear in mind full males, and I assume he is a full male and not neutered, wander far and wide. We now have half ownership of a cat we call Buster, who used to visit us as be a full male and "sing" to our neutered female - hope springs eternal presumably - before he came to us one day last year injured, and was repaired and neutered by the RSPCA before being chipped and returned to us - and now we see him once every three months or so - once a wandering tom always a wandering tom I'm afraid. So one other suggestion is the local Cats Protection league - they may help to trap and neuter a full male who is causing issues - PM me for contact details if you wish - do not really want to post them here