Gooseberry sawfly can strip the leaves- sometimes overnight-not sure about the fruit.
Like most things this year I'm inclinded to blame the weather, there are few gooseberries on my bush too. They do however need a lot of water to produce fruit, I guess they haven't liked the cold and windy spell.
Frances, I had exactly the same thing last year and I never found out why. It had to be something that could creep in under the netting - a whole troop of mice or larger rodents was the top suggestion. I also lost two entire - though smallish - cucumbers from the greenhouse when I forgot to shut the door one night.
We also lost gooseberries overnight a few years ago. We had harvested most of the crop but left about a quarter of them to ripen to eat raw (my daughter is very partial to them) the next day they had all disappeared. We assumed it was birds as we don't net them. This year, yesterday in fact, we picked the lot, have frozen most of them and made my first batch of chutney. Not taking any chances!