Having just responded in part to the second prompt in the Book of Me project. I thought I would share with you some factual details, which may be worth noting for those of you in the UK (and I suspect other Countries will have similar issues).
In 1989, the Children's Act was passed through Parliament. That act came into force in 1991. As part of that Act there was no obligation for social services departments to retain old case files. This means that those files may have been destroyed with a potential a loss of private data.
The disposal of early files will depend on the social services department involved and the criteria that each individual department had. The rule of thumb is typically, 6 years from the last case entry or when the individual became 21 years of age.
There is an exception with adoption cases, but that is not the case with those who were almost adopted - for example those who were going to be adopted and then were not.
The message here is in essence if there is a social services file (or indeed any file) about your early years make an application to receive copies. In the UK there is a fee for data protection access, but do it before it is too late, and is shredded, as I said previously, there is no legal obligation for record to be retained.