Have you zoomed right in on the pic, the fruit are covered in some sort of aphid when I look at it zoomed right in on my phone, no idea what treatment needed, good luck saving your fruit x sorry if you had already spotted them x I'm a total novice just wanted to try n help x

Is this happening to all your fruit? If so, I suspect the damage is far more likely to be from a fungus (mildew) than aphids, especially grown inside a greenhouse and with the damp and cool conditions we have all experienced so far this year.
I can't see this in your pictures, but the safest thing to do would be to spray lightly with a copper based fungicide like Bordeaux mixture and to allow maximum ventilation in your greenhouse.
Vines like to be well aerated and do best outside, though I appreciate it is not easy to ripen fruit in cooler climates.
What variety of grape is your vine? If it's a dessert grape like Black Hamburg then this does need some heat to ripen but is very susceptible to fungal attack. There are many other grape varieties that will do fine outside or with a little protection for the fruit.

Thanks for the advice.will get some bordeaux mixture.the growth is just on the grape not the leaf or any other plants in the greenhouse. Thanks again