You can buy a plant which cats detest and move it about when required just keep it potted.details below, hope this helps. g Coleus Canina [cat shoo] height and spread 60cm grey/green foliage , blue flowers in summer plant in a container and move around when needed.
Try sprinkling ground black pepper. It worked for me when they used to sit on the roof of my convertable and ruined it. They never returned when I put the pepper on it
Black pepper or pepper dust is ok but the trouble is if it's windy or raining it's of no use.I have three cats and this plant is the best to keep my cats of my flower beds.