Fungal infection on Damson

I have a well established damson tree in my garden, but the fruits are suffering with a fungal infection causing them to elongate and shrivel up. When we moved in the tree was very overgrown so I’ve pruned quite a lot of the dense growth from the inside of the tree to help improve light and air flow. Can anyone comment whether they’ve experienced this before and advise whether the tree can recover from this? There are still some healthy fruits, so all is not lost this year, but hoping to improve it for next year.