Thanks for the feedback everyone!

I think I'll suggest the two middle name option Zara Elizabeth Eternity.

I'm ok with having two longish E names as it's kind of another reflection of my Nana's name which was Dorothy Evelyn Elizabeth and our surname is quite short.

Plus Eternity is one of DH's better suggestions - beats Sunshine, Tuesday and Aurora in my opinion!

Now, to wait and see if we actually have a daughter!