I am indebted to you for one Agimatic top plate, I believe? I haven't forgotten
There seems to be two separate schools of thought about fungus, even inside the optical industry.
Some believe it should be treated like a highly infectious disease - fungus must be quarantined and kept away from other optics in case it spreads like an epidemic.
Others believe that the spores are all around us, everywhere and that fungal growth in a lens or camera is the inevitable consequence of storing the things in the wrong conditions. If the conditions are not favourable to fungal growth, it doesn't matter whether spores are present or not, they won't grow.
I must admit I'm of the latter tendency. I work with optics full time in my day job. I've never, ever seen a problem with fungus or mould growth in any optic that was kept in 'normal' conditions. I've seen plenty of fungus in things I've bought off eBay that have been pulled out of someone's garden shed.
In this case, though, you say the growth is inside the camera? On the chassis and metalwork presumably?
I believe the fungi that grow on lenses are very specific species. Some like optical glass and some specialize in the balsam between cemented lenses. They are completely different to the stuff that would grow inside a camera body... which might be a mould growing in the damp dust inside the camera rather than a very specific lens etching nasty.
Killing fungal spores may be difficult, I'm not a mycologist either so I wouldn't know, but I think killing growing fungus and moulds themselves isn't so hard?
Bleach, ammonia, acetic acid, hydrogen peroxide and heat should all kill it off. I think it is a matter of choosing something that won't damage whatever it is growing on.
I recently bought an ex RAF whole plate camera on eBay. When I went to collect, the seller whipped it out of their deep freeze!
Apparently it was riddled with mould. Actually, the mould was mostly attacking the case the camera was in - but the bellows were pretty mildewed, too. This was their usual, if unorthodox, treatment. It seems to do the trick, after I cleaned the dead mould off it has shown no sign of regrowth!