Technical Panda 2015 Lounge roof bar bolts

[RobRoyToy]

Hi all, I have roof bars for my panda but not the bolts for fixing them to the roof rails. I have been to a local fixing firm but they cant find the correct thread size ? I was advised to contact a Fiat main dealer but they don't seem interested ! Seems such a simple job but no one knows. Can anyone help, thank you.