Kenn or Yatton birth

[Hackstaple]

My ancestor Eliza Nethway appears to have been born either in Kenn or Yatton and either in 1809 [favourite] or 1800 [less likely]. It may be that her father was William Nethway b. C 1781 d. 1831 and Hester Baker b. C. 1784 They had one sone that I now of and he was also William, born C. 1810 and died 1858.
The Nethway name was relatively common in the area but today extinct. I am trying to find a baptismal record for Eliza.
Secondly, I am trying to find out how and why she got to London where she married Henry Demery in 1829. Previous quests have shown me that such moves within the working classes were often as house servants and so she may have gone up in that capacity for a local family. That would not have been a fabulously wealthy family as those usually kept two sets of servants. Similarly, not perhaps a farming family as those tended to stay at home. Perhaps the local MP?
Those are just guesses but anyone who has any good ideas or access to parish records please let me know.