Further to my answer I read the link and they are not green but brown so I could be well wrong saying sawfly Mine were green about one centimetre long any clues
I've seen some of the devastation that the moth grubs can cause to gooseberry plants (not pretty) and can strip the bushes bare in some cases.
I've been growing a variety that is said to be disease resistant, for a couple of years and so far so good, its called 'Hinnonmaki red and has the larges red berries of all.
Don't worry. the wild bushes in our hedge row are stripped bare every year and they re-grow leaves and produce fruit without anyone doing anything.
You could give the bush a feed with a high nitrogen feed to encourage new leaves.