Hi All - and Cindy, I'm laughing my head off. I just switched on the lap top to reply to this now (sorry, have been super busy over Xmas) and there you are !! Is there no hiding ?

I was 100% positive on Anastasia Featherston after seeing the record that Tara posted on Elizabeth's birth. (Thanks !)
I had never seen that version before, just the FamilySearch version with only Eliza Heavy's name listed - I was pretty gobsmacked by that. (also that William Coffey crops up again as an informant to one of Anastasia's children later)
I was able to put this whole scenario to an older Brophy's over Christmas and he was not fazed at all and claims to clearly remember hearing Anastasia Featherston's name mentioned before.
So, I will of course get certs when the Office opens up again, but all the info fits perfectly. The only disparity I found earlier was the little Eliza in Glasnevin - (6M) seemed to be one Eliza too much. But if she is Patrick Brophy's child then that makes absolutely EVERYTHING fit into place.
As I said, I had completely dumped this line of inquiry, in favour of the Fitzpatrick lady - but could get no further and was hoping for a fresh perspective on it all - and sure enough I got it in spades. !!! So thanks to everyone who spent time looking (I know only to well - the time involved)
I found that Anne FitzP her husband Michael B and daughter Bridget were all deceased by 1910. (Typhoid) but still have an inkling that there may well be some connection there - so will keep them in the loop for now.
I did a little more digging before Xmas and it seems Michael Brophy died in the North Dublin Union Workhouse in 1894 from TB. So, not all happy there either.
And Cindy, Re: Eliza d.1868. No - all but one of the Glasnevin Records are single page with very little info.
If the certs do not show that Michael Brophy was a widower, when I get them I will eat my hat !!! I will let you know.
Thanks again everyone and a very Happy New Year.

@Cindy - I tried to find you some Shannon info over Xmas - but just got a few anecdotes and a couple of possible names in the younger generation - Will mail you.