Hi Paul
Those are effectively extra tall cheese-head screws, I have an Empire Baby S/N-7434 with the same setup. I don't know about the Hermes Baby, but the screws on the Empire are secured to the back of the body with nuts. A pair of modified Mecanno screws and nuts may be a possible solution. Tom The Typewriter Man would be your best bet for sourcing replacement or similar screws. Hope this points you in the right direction,
Sky
We humans go through many computers in our lives, but in their lives, typewriters go through many of us.
In that way, they’re like violins, like ancestral swords. So I use mine with honor and treat them with respect.
I try to leave them in better condition than I met them. I am not their first user, nor will I be their last.
Frederic S. Durbin. (Typewriter mania and the modern writer)