Re the 1919 birth certificate that has been annotated.
Was an RCE issued to include this information?
I have discovered at least 2 birth records for my family where a late RCE was issued to amend names.
Both were well into adulhood when their RCEs were issued.
It took me a long time to work out what this was.
In both cases the biological father had died when they were infants.
Both had been raised by step fathers and both had always used their stepfathers last names.
I came to realise that in adulthood, both of these people required a passport but, of course, neither could supply a birth certificate in the name that they had always used.
It was done by RCE. ( 1960 and 1990)
This did not alter the birth details in any way, but, simply showed the name that these people had always used.