Hollyhocks leave in pots or put in ground?

[FinishedAtFifty]

They are about 20cm tall. I have a very slug/ snail garden. Leave them in their pots over winter or put them in the ground?

Leave them where they are. In theory they are perennials so should shoot up again next year. Even if they don't, they may self seed themselves in other places and pop up around the garden in unexpected places.

@TonTonMacoutethey haven’t flowered this year as they are too young so no self seeding.

I'd plant them out as they grow a very long taproot, so to get them to bush out and thrive, it's best in the ground. Give them a good 80cm apart to give space to leaf out. They'll die back over winter, and then come up again in spring.