This clip is widely used by Vauxhall to attach front and rear bumper trims. The clip is a simple push fit plastic rivet that fits into a 6mm hole. They are used on several models of the Astra, Corsa, Meriva, Tigra, Vectra.
These clips are not universal. Different models use different styles and styles. Please check the photo, part number and dimensions to ensure that they are the parts that you need.