Who is the culprit?

New to this grow your own and gardening on general this year. Got a variety of things on the go. Slugs are an issue but not too bad. Fruit is under a net so the birds aren't a problem.

I am though getting more and more foliage nibbled at. I am guessing not slugs as the tend to start at the outside. Is this the work of a caterpillar? So far they just seem to be attacking the leaves and not the fruit/veg. Do I ignore the little buggers or do I form a counter attack. If so - what exactly. This pictures are potato, beetroot and broccoli leaves.