what is the fruit

I think it's probably physalis franchettii, commonly known as the Cape gooseberry

I agree with Andrewr...

Thank you both so much it has been bugging me for weeks since I was given the plants. They are growing fast and I cant wait to try them.

These are perennials so will come back each year but the roots do tend to run so you may need to curb it

It could also be Physalis peruviana/edulis. If the leaves are downy and the papery case is beige when the fruit is ripe, it's peruviana. If the case turns bright orange it's franchettii. I'm not sure whether franchettii's edible but peruviana definitely is - with a pleasant slightly tart almost pineapply taste, but I don't get many on a plant.

Physalis, Cape Gooseberry, Tormentollos, Lantern fruit etc., are common names for this plant and the fruit go great with melted chocolate!!!!