The hot May has been a nightmare for many plants, including unlikely plants like beans etc!
Our blueberries have succumbed the same way as yours, such that we may dig them up and pot them somewhere else and use the space for another crop of something or other.
Tayberries are usually such aggressive plants, (not only the thorns, which can maim at ten paces), but I'm afraid you've just had a bad start this year, it's not your fault - next year will be better!