I have today received the birth certificate for the third of the three children that are relevant to this thread. As some of them are living I shall disguise the names as follows:
Mother’s maiden name Delta
Mother’s married name from marriage in 1905 Romeo
Father’s name from birth certificate (and name the children were brought up with) Lima
Important fact – Mr Delta sued Mrs Delta (nee Romeo) for divorce in 1919 naming a co-respondent who was not Mr Lima. At that time Mr and Mrs Delta had had 5 children, all of whom are in the GRO index under the name of Delta with mother’s name Romeo (those after 1911). I have not yet been able to check whether the divorce became final. There is no sign of a subsequent Delta/Lima marriage.
There are then three children after the date of the divorce petition who are listed in the index in 1920, 1921 and 1923 as:
Child Surname Delta mother’s maiden name Romeo and also as
Child Surname Lima mother’s maiden name Romeo.
The GRO Reference in each year is the same for each of the entries. I ordered the birth certificate for the 1923 child using the surname Delta (the original name from the 1905 marriage). The certificate received has the father given as Mr Lima and the mother as Delta formerly Romeo.
I don’t intend to send for the certificates for the two older children. I think it is probably fair to assume that the pattern would be similar.
All of the above would go to confirm, as the family today have always believed, that the three later children were fathered by Lima. The birth certificate is a straightforward reflection of the facts.
While waiting for the certificate, I emailed the GRO outlining my query. The essential part of their reply is:
If the parents' surnames recorded at the time of registration are not the same, the birth will be recorded in the indexes under both the mother's and the father's surname, which is what we call a dual registration.
None of this will be news to many of you, particularly those who had already given me the answer in a different form of words. I must reassure everyone that continuing with the thread does not indicate disbelief or that I was ignoring your answer! The certificate, as has been said, helped to clear it all in my (becoming) addled mind and I promised to post the result so here it is! I am content that I now understand what was going on so thank you to all who showed interest and gave me the benefit of their superior knowledge of these matters. I am off to seek a darkened room.
maxD