As far as the Pinnock's go I have nothing other than William's father George. The question regarding Edith was (I think) something to do with the names of the fathers shown on marriage certificates.
If you look at your Great Grandmother Sarah Pinnock nee Briggs, then that line I have back as far as 1830. Herein lies a tale - George Briggs (Sarah's father) was born out of wedlock in 1853 by Matilda Briggs. The father I have discovered was a scottish fella Andrew Scott who she married after George was born. They then had another son, Walter, who had the surname of Scott.
Curiously, both George and Walter lived in the same street in Tibshelf (where my Mum was born), so they were brothers with different surnames!!
When I get back to the Tree, I will be looking more closely at the Pinnock side.
As you say a small world with Slough. What road do you live in?
Regards
Kevin