It was particularly exciting to see some tell-tale circular holes in the leaves of this, now not so little, plant in mid-March. On investigation, I found that the culprits were two caterpillars of the Scarlet Tiger moth. Hopefully there are more.
The females like to lay eggs on comfrey and nettles, but in this instance Alkanet seems to have been the plant of choice. After seven days they will have hatched and overwintered as 15mm caterpillars in the leaf litter. They become active in March and as they get larger they may wander off to find other plants such as bramble to munch on.