Caterpillars are the most likely culprits esp is the leaves are shredded looking. Look under the leaves for them - there may be a few dozen of them and quite small.

Gooseberry sawfly is the most likely culprit. Give the bush a high nitrogen feed and it will soon grow new leaves. The ones in the hedgerow along our lane suffer this every year and still produce fruit and grow well.

Ah yes Sawfly larvae are caterpillar-like but not caterpillars as such.

They are amazing - can strip a bush almost overnight. We used to use Derris dust on them before it became a NONO.
(I'm talking early 1950s here...)