What is this plant?

[Leftittothelastminute]

Hi all, I have this plant in a pot and want to get another one but I have no idea what it is! It flowers in the summer and survives the winter! Can anyone help with identifying it please?

could be Calibrachoa or Million Bells, there are a few cultivars with white flowers, your one looks to have double petalled flowers

Thank you- that looks like it!