A lot to catch up with John, but thank-you so much for helping out. Where to start...
I did know about Thom J's son Thomas being born in Bedford, and the date. With things as they are here at the moment, I will not be able to apply for the certificate for a while, but as things progress I will keep that in mind.
My mistake! I did have that Augusta Amelia was living with her father in Bedford prior to the marriage...I will blame the medication.

I did not know a witness to Thom J's 1st marriage was a Godfrey Young, neighbour.
We have noted about Charles Albert, Edith Rosina and, later, Herbert Walter. Your locating Augusta Ann was a surprise though. Commercial Traveller is what we had Thomas J as...'a gent' may be stretching the point!
Have Augusta Amelia in Bedford on 1861 census, with 2 of her children. Still have not been able to locate where our Ernest Thomas was though...he would have been c 2yrs old. Neither have we located Thomas J for that year, but being a comm; trav; he could have been boarding anywhere.
In 1871, we have Augusta at 339, Kentish Town, London...along with her children and her sister Rosina Amelia who is working as a governess.
That same year, we have Thomas J as boarding at 30, William Street, St George the Martyr, Southwark...he being 48 and still a comm; trav; of, (so it states), Walworth. This would make his birth year something like 1823. That's some leeway between all possible dates of birth for him so far.
The lists written up on Anc*** regarding Maria Louisa seem pretty close to a lot of what we have about this Priestley line...always assuming we have the correct info! It is entirely possible she would have been, (along with the other siblings noted), allied to Thomas and the Benjamin we had already have, but have not followed up.
If phveens can get hold of some documented names and dates then that should be easily resolved.
That was fantastic locating the burial of the young Thomas. Wondered if he had died as we had not found anything positive about him in later years, but not persued it too much.
Thank you John...Shalena