Thank you for reaching out! I do hope that you find more answers about your birth mother.
You are right, there wasn't a census in 1923 that would have easily recorded your mother's birth. That said, if you happen to know where in Ireland she was born, then you may be able to search locally for civil and parish
records. Unfortunately, while this may help you learn more about your mother's place of birth, it will not list her siblings. Other resources, like Roots Ireland
, may be similar in that regard.
But that doesn't mean that there aren't records to be found! In fact, I'd recommend checking out ship records
, to see exactly when your mother travelled to London and if it was possible that she was travelling with someone.
I do hope these resources help!