Thanks for all this detail Millmoor. What a (typical?) family.
Sarah Jane 1888 looks to be a Whitchurch registration, but the censuses keep showing Bradeley Green, which must be on the Cheshire/Shropshire border; taking her back home for the baptism is not surprising, but nice to know. I'm still looking for a Joseph marriage to an Emma, if it actually took place.
I'd got the 1869 Edward Griffiths/Elizabeth marriage and have found seven children, from William to Florence Elizabeth, but hadn't got to the 1871 Census record and so hadn't spotted Joseph; he's not with his aunt in 1881 in Prees.
Elizabeth, Jane and Tamar were sisters, among the children of John and Eliza Saywell.
Everything does just about make sense. From a research standpoint the variations on the Saywell surname here make for an object lesson in lateral thinking: Saywell, Seywell, Sewell, Taywell, Leywell and so on.
Regarding the issue of the two Janes, I conclude that Jane, sister of Tamar and daughter of John & Eliza, married Joseph Bayley (sister Ann as a witness helps clinch it). The other Jane married John Hough, widower of Tamar, daughter of Thomas & Emma; it looks to me as if her only sister Emma died late 1865 with the burial on 02/01/1866 at Wem, aged 22. I've not found Thomas and the re-married Emma (Hough) Parry after the 1851 Census entry at Coton.
I'm not sure if there are any more twists in this story, but my sincere thanks to all contributors thus far. It's so helpful to bounce ideas off like-minded people.