You said you agree everything should be released under PII is that correct
Yes that is correct, however I would need to see the wording of such a petition.
NGB will likely be able to inform you that in the first instance many items which have not been released, are not actually withheld under PII, some items have just simply not been released. You should also be aware that the laws regarding PII did not exist back in 1985/6 in the format they are today.
There is also a process for applying for the release of documents.
But show me the wording and then I'll decide, can't say fairer than that.