You can buy generic metric 8.8 high tensile bolts mechanically galvanised from the right bolt shops (or online).
I haven't looked for 10.9, but they're probably around too if you look hard enough.
You can also buy generic control arm fastener kits from VW/Audi, and I think Meyle sell them too:
Eg,
N10425302
N10770901KT
That was just a very quick google, so with a bit more effort, you shoikd be abke to find something...