TreaderSteve
Senior Retro Guru
I'd ask on here for an ally wedge that takes M8 - yours looks, to my eyes anyway a standard/ familiar angle of wedge.
Then get one of these - I've used these several times and for me are good value. Scroll down a bit - various lengths - including longer than you require.
https://titanclassics.com/product-category/nuts-and-bolts/titanium-m8-allen-head-bolts/
They sometimes have them on Ebay too from this seller
Then get one of these - I've used these several times and for me are good value. Scroll down a bit - various lengths - including longer than you require.
https://titanclassics.com/product-category/nuts-and-bolts/titanium-m8-allen-head-bolts/
They sometimes have them on Ebay too from this seller