Immature fruit dropping

AussieWayne starts with ...
Hi guys I have a Nelly Kelly on grafted stock (I think) that earlier this year produced its first major crop of maybe 300 plus large healthy, delicious fruit.
This current crop started well in Spring with heaps of flowers and even some bees doing their stuff and a lot of the buds have turned into fruit but they are dropping from the vine at what seems to be a node above the bud node?
Some are even wrinkling up and dropping as immature fruit?
Does anyone have any idea what might be causing this drop of maybe 80 or more immature fruit this time? There are maybe 100 large healthy fruit still progressing.
I do fertilise with both Seasol and a fruiting fertilser. Generally gets watered everyday and overall looks healthy although there are a lot of ants in and around the vine. No other obvious pests? No pesticides used only a home based kitchen concoction that helps with the ants.
Location is Gold Coast close to passive salt water creek.
Tried to capture the story in the photos as best I could.

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