Non-fruiting quince AND Kiwi fruit

I have a Jenny kiwi fruit that produces loads of blossom but no fruit. I have tried hand pollinating to no avail. The flowers just, eventually, drop off. It is on a south facing fence and is about 7 years old. The quince is a Vranja variety and is about 4 years old. 2 Years ago I had limited blossom and 3 fruits. The past 2 years I have had (again!) loads of blossom but no fruits. On both kiwi and quince the bees have working in them during flowering, but the flowers just fade and drop off. Any suggestions??