Hi Hazel,
Sorry i dont have Longcot, Sparshot or Childrey PRs but did search surrounding villages
but came up with nothing im afraid.

Martha Maddons/Maddoms i couldn't find her baptism either. I searched Steventon as this was
where they married also Abingdon and all nearby viillages with no luck

Ok i did find this from Charney Bassett PRs
Baptisms
Jan 14 1756 Robert Roby son of Robert and Anamaria ( incase you didn't have it )
Children of Robert and Martha ( name spelt Roby and Robey )
Oct 15 1780 William
Aug 31 1788 Anna Maria
May 23 1790 Mary
Jan 27 1793 Giles
Jan 25 1795 Martha
Other children it says parents Stephen and Martha

Also why such a big gap between William
and Anna Maria

I then searched Burials and found the following
Sep18 Martha Roby age 64
Jun 3 1828 Robert Roby age 72
Nov 13 1839 Martha Robey age 72
Oct 6 1841 Stephen Roby age 80
I went back and searched again and found Stephen was Roberts brother.
I can give you details of Roberts brothers and sisters if needed

Let me know your thoughts on this please

Sue