Steve wrote:

Last year I had a major problem with ants, although the tomatoes were left
alone the carrots were chewed to death.

If you mean the leaves, then most likely that was slugs or snails. If
the roots then carrot fly.

Although I dug out where I thought the nest was, this year they are back.

How do I get rid of them?

Ants are *everywhere*. I don't think it's remotely possible to get rid
of ants outside, but they don't do much harm either, so relax. Or
rather worry about something else instead...

Peter