Have you found them on the 1841 Census? - it might give some idea of their ages. I had a brief look on freecen but I don't think they've done that area yet. On Genes Reunited, which you can search for free to a certain extent, there are lots of Parkers in Gloucs, especially in and around Cheltenham, but none in Whittington or Hawling. Without seeing the census entries, it's difficult to see how they are all related. Maybe somebodyelse will be able to do this for you if you don't have it already.
On pilot.familysearch (from registers) there is a Hannah Haynes born 20th March 1803 at Hawling of John Haynes and Hannah. They have a raft of children all christened at Hawling - Amy 1794, Emmet 1793, Thomas 1799, Jon 1805 (you can see all the exact dates on the site) and an Elizabeth ch 5 Feb 1797 who is probably the sister who marries Charles Parker on 28 Jul 1823 at Charlton Kings.
There is also a marriage for John Haynes and Hannah Kilby 6 Feb 1793 at Hawling who are probably their parents.
You would have to verify all this of course, but it gives some starting points.
Apologies if you already have all this information - you never know! - it's not too long since I found the site myself!
Happy hunting
