Hello suemo, ;)
Just a guess, you may have been hit by an infestation of green fly, I had a lot on my bushes, & sprayed them with ultimate bug killer from provado, some of the bushes were very badly damaged, & have not recovered. The fruits shrivel up & do not develop into fat black berries >:( Are the leaves on your plants all curled up & stunted? Look under the leaves & you may see the little blighters in their thousands. If you do not want to spray, you may try rubbing them off with your fingers.
Adrian.