After hitting a post the bumper on my Punto split from the bottom to the fog light assembly
Nice clean break

I found on Ebay this product "J-B Weld" an epoxy resin specifically designed for plastics such as ABS, PVC, Fibreglass and they even quote glass
Made in Texas, USA
Setting time on 5 minutes and cures within 1 hour

Worked a treat, for about £6 gave me a perfect repair
Saved me a new bumper

I daresay Fibreglass may have worked but this is far easier