My ginger cat, approx 8 months old, will not use the garden for his toileting. I took away the litter tray when he was old enough to go outside but we had several accidents of both varieties in the house. I put the litter tray back but in the garden and he will only use this. He can get in and out of the cat flap but doesn't really like the outside. Any suggestions as to how I can teach him to not use the litter tray anymore? Thanks!