Many Thanks to Janelle-Jbml and Bostin Lil for taking the time and interest, to reply.
My theory...may be a bit too simple..Charles Mills, although not married to Cath's Mother Sarah Ellis
(Mills 1841+51 cens.) was possibly a step-father to Cath. step-grandfather to her children
Bapt.Sarah Littlewood 1797 Sheffield Yorksh. Parents John+Catherine
(Found Sarah's mother + siblings in census at Quarry Bank kingswinford Staffs))
Sarah has an illig son John Littlewood 1820 Dudley Worcs
Correct marriage 1821 Kingswinford Wlm Ellis + Sarah Littlewood
Bapt Dudley Cath + Edward Ellis 1824 parents Wlm + Sarah
Possible burial St Thomas Dudley 1829 Wlm Ellis age 33...age near enough fits with..
Baptism Wlm Ellis 1797 Oldswinford Worcs Parents Wlm + Elizabeth
1841 Charles + Sarah Mills + Cath. Ellis Dudley
1841 John Littlewood (1820) lodging next door but one..to John..Edward Ellis (have Edwards
marriage info. Father Wlm Ellis shoemaker (dec)
1851 Charles + Sarah Mills + Cath Ellis Dudley.
1851 Birth John Evan Ellis (When I applied for cert.mothers name correct but no father..so did'nt
buy)
>>>
So Jackie,
forget that unhelpful professional, dismiss her from your mind !!

Can we please have a smiley doing a thumb-your-nose-action, I think that would be a more appropriate sentiment for what I feel on your behalf than the "mild' sticking-out-of-tongue.

You have your Ellis Mills Littlewood people sorted clearly enough.

Being able to peg them every 10 years in census is wonderful.

Have you told us when Charles Mills died? do you have his cert? It might be interesting who was the informant, might fill out his place in these women's lives.
Just a shame that the father's name is so often not entered on birth certs of single women's children, as is your John Evan's case.
Me, I would buy all and any certs anyway, especially if the person was my direct line. I would want that piece of paper, especially now that the GRO is all digital and you get a copy of the real original entry, not a contemporary handwritten certified copy.

Salute,
Janelle