I have large pots on my patio which throughout the year have a variety fo different plants in

Empty out your pots and give a thorough clean. Raise them up off the floor with pot feet or stones or anything that works for you. Cover the drainage hole with a piece of Jeye cloth or similar and refill the pot with new compost. You can put the old compost in your compost bin.

Thanks - have tried everything except the J-cloth - will try that :0)))

I'd put a layer of gravel or small stones in too to a) keep the J-cloth in place and b) help with drainage.

Sprinkle Cayenne pepper on top of the soil. It won't hurt the plant, but the ants, slugs, snails, and worms don't like it. Squirrels don't like Cayenne pepper either.

The ants don't get into the pot from the top they come up through the drainage holes in the bottom.