I'm not sure how you would find her family on any other census, without confirming from 1911 that they do indeed have a daughter Irene!
Especially as you have pm'd to say you are not happy with the one I did find!!
I'm sure there are many Henry Davies who are coal miners around in Wales, seeing as it is one of the most common names and occupations, so from the other censuses alone you will have no way of knowing if they later had a daughter called Irene.
Where did your date of birth for "your" Irene come from? Was it just from her death? If so , remember that the information given at death was only as reliable as the knowledge of the person giving it. Not unusual for it to be a year or two out.
Likewise, census ages can be slightly out - not unusual for a dad filling in the details of his 9 children (as is this case in the census in question) getting one of their ages a year out!
I wouldn't rule this one out too quickly.
Who were the witnesses when she married? Maybe they are siblings, which would help rule this one out or in.