Ok I've added the bikey to a new keys folder within the mod and signed the pbo, hope this does it

weird, I've looked up how to generate keys but I cant really find anything apart from bisign stuff

There is no keys folder, which is normally standard. Alternatively there are no bikey files anywhere in the mod folder only the bisign is present next to the PBO. But without an bikey file the bisign is useless.

I'm fairly certain there is one

Could you provide the bikey within the mod? This allows us to use signature verification.