Hi Liz,
To be honest, I am not sure whether she is a member of this same family, or whether it is just a coincidence. All I did was look for children born with the same surname/mother's maiden name combination in the right time period.
Have you heard of freebmd?
https://www.freebmd.org.uk/cgi/search.plAs its name implies, it is free to search and you don't have to sign up. When searching, tick the 'Births' box, enter surname as 'Plumb' and 'Spouse/Mother surname' as Cripps. There you will find a list of all children I mentioned.
The only thing that supports there being another child is the redacted entry on the 1939 register. There are 5 members of the Plumb household: Samuel, Esther, Daphne & Ralph + 1 more. The fact that the entry is closed means that this person is either still alive or only died recently and the page has not been updated to reflect that. I suppose it could also be the male Plumb born in 1923, although he would be of very advanced age by now.
Queenie
