Elsie Nest Jenkins was born in 1894 Pontypridd.
There are 2 births which may or may not be relevant
Mervyn J Stephens 1916 mother Jenkins and Leonard H Stephens 1917 m. Jenkins
None of these appears to be on 1939 register.
Can you name the child or would you rather do it by private message.
Does Canada figure in your search Peter, because some records show a Leonard H in Canada and
Selwyn James Stephens born 1892 died in British Columbia in 1970.
Update,
1962 voters list has Selwyn James Stephens and wife Elsie at 4114 Venerables Street, BC, Canada
Shipping lists show them going there in 1921.