Must say thank you to everyone who has tried to help with this.
I can now say thanks to Softly Softly, I’ve finally got the correct person. The birthdate on the death certificate was indeed wrong,and should have been 21st June 1919.
So Elizabeth’s mother was Annie Maginnis, and her father Patrick McKeown. I haven’t been able to find their marriage as yet or any siblings for Elizabeth,but will keep hunting!
Once again very grateful for all the help.