It is delightful to be able to email my sister - and I have now sent her the excerpts which mention our father in the book I came across (see 9th January). It affected her as much as it did me. We neither of us know that much about him, or his family, or that period before we were born, as we missed out on normal 'family nostalgia' and fireside stories (couples separating was all a bit more secret - shameful? - back in the 50s).
There's certainly a genetic connection across the generations - but it takes different forms. For instance, I would say I had my mother's face/eyes and my father's body, and (to some extent) temperament. Broad generalizations, of course, but perhaps there are small insights to be gained from such speculation.
I think I'll publish some of it - as I think the family portrait needs to be a bit 'warts and all' to be valuable.