My latest attempt is to paint the rims of the pots with engine oil. It only leaves a thin film, which will probably need renewing at regular intervals, but if little nuisances don't like the taste, maybe they won't cross the rim.
Then we can eat the beans, instead
Time will tell.
If there are any hedgehogs around the garden, and there used to be, they are welcome to feast to their hearts content, ditto for frogs or toads in the pond. Pity thrushes seem to be in short supply!
Howard