Hi Peter
Posting on every board where a birth for a Margaret I Anderson is listed can cause a great deal of confusion and duplication - particularly as people will possibly ask the same questions each time
There are a great many Margaret I Anderson births in a great many areas and you have no idea of her birthyear or her birth county
Reading part of the post on the Liverpool FHS board - you were born in Northants in 1940 but Margarets address on your birth cert was in Liverpool. The Liverpool address has yielded nothing, nor have the other links provided for you
Have you considered that Margaret could have been one of the many Irish or Scottish girls who came to England to have their babies and then returned to Ireland/Scotland after the birth?