Hinge plate bolts

[Stonehopper]

These have a wierd shaped slot in the head. Countersunk, part groove part hole.
I have nothing in my arsenal of tools that will shift them. Does such a male socket exist? None of the regular parts suppliers have anything like.

Bit fuzzy, but they should be visible.

[myglaren]

I have a couple of sets of security bits and checked but there is nothing among them suitable.
In the past I have just used a suitably sized screwdriver but usually had to give it a belt with a hammer and punch on the outer edge to get it started.
Perhaps you could grind a large enough screwdriver to fit the slot better than a plain screwdriver?

[Stonehopper]

I think you are correct. Darrin at Citroen Classics in Staines has said he has not found a tool that fits, but used an adapted flat bit in an impact driver.
I'll be looking at concocting a special !

I expect Mr Moss will have something - at a price.