M6x16 socket button code 28496
Socket cap M6x20 code 19472
M6x20 socket button code 25864
I will be measuring and replacing some more as time passes and adding the codes as I do. I used a Screwfix set of stainless bolts when I fitted crash bars to a former bike. They were pristine when I sold it 3 years later so it must be pretty good metal. And they are a 5 min ride away which helps.