Nibbled and in some cases cropped. We're in an enclosed garden, with no sign of ANY wildlife.
The only other clue is that in that area if I sprinkle green slug pellets at night by morning they've all gone. So maybe it's some nocturnal critter?
It's not rabbits.
It's not slugs or snails.
Have you looked for signs of caterpillars? They tend to eat early morning or late afternoon. During the day, you can find them on the underside of the leaf, they often they move to the base of the stem during the day. Look for signs of caterpillar poo - small back pellets. You would be amazed how much damage a couple of caterpillars can do. If you do find signs of caterpillars your best choice is Dipel, it contains a bacteria that specific to the guts of caterpillar and will not affect other insects or animals.