I have now had time to really sit down and look at this properly. Thanks all so much. I really think you are all on the right lines and it's the correct family.
The 1908 John Hoare marriage is wrong as I found a John Hoare (a widower) living with his parents in law who are Tiernans so the 1911 census and that makes the match for that marriage Mary Ann Tiernan.
So it's going to be one of those Bridgets matching the John Hore and a 1908 marriage.
I'll let you know what that birth certificate says (though I am prepared for it to be the wrong one!).