Hi,
Besides the big age discrepancy of 10 years with the Wolverhampton birth in 1917 birth ( which is West midlands), I think the 1917 birth is likely to be this lady below as Southampton is not really anywhere near Wolverhampton
Name: Ethel D Swatman
(Spouse Meredith )
Marriage Sep 1953 - Bilston, West Midlands
I tried both ancestry and freebmd with a search term of *man so it would bring up all surnames , misspellings and all ending with man. There doesn't seem to be any likely births for her in England and Wales that I can find.
There is a public tree on ancestry which the owner of the tree has put the Wolverhampton 1917 birth for your lady and the 1947 death . This person has the parents George Richard Swatman and Sarah Ann Preston , no siblings on it. "Molineux Family Tree " . I don't know how well the tree is researched, but I'd tend to tread carefully especially because there is that above Ethel D Swatman who marries around the same area as the 1917 birth
There could also be a chance that she was not registered with the middle name and acquired her name of Doreen when she was christened.
Can you tell us a little more about your Ethel as mentioned by Kilkennylass?
Can you tell us the names of her siblings? Is your direct ancestor one of her siblings? If so , did the family/her parents stay put in England? Is there any chance at all that she may not have been born in England and Wales?
Have you access to ancestry or alike? If so, another suggestion to rule out that she is definitely not registered in England and Wales around the time frame is to manually go through the images of SW births page by page , say from around 1925 to about 1929, if you've not already done this of course.
It does happen that some entries get missed out of being transcribed. Also depending on what site that you are searching for her on , sometimes there are missing pages too ( I know that ancestry has had some missing quarters in the past when I have scrolled through some of the letters).
Kind Regards