"As for the people that pointed out she would probably be shorten down to Murf or even Smurf we had considered that and we probably would call her either of those as a little nickname whilst she is little, we are from Kent so I doubt she will be called spud"
She will be called Spud.
Or Chips.
Or maybe even Mash.
There are many unique, unusual and attractive names. Murphy isn't one of them. I think you should be thankful that you have received an unvarnished response here before committing a child to a lifetime of saying 'Yes, it's Murphy. Yes, the Irish surname. Yes, my parents knew about the potato thing...'
I agree with the cultural appropriation point made by Harriet. It's distasteful.
And there's more to it.
Many Irish surnames are composed of old first names (the Irish surname system of Mac and O and Nic and Ni basically refers to son of and daughter of). So use of those names as first names is in accord with an old tradition.
However, when Anglicised, the feminine forms of the surnames were cast aside. Everyone became Murphy or O'Neill or McGuinness, etc. instead of nà Mhurchú or nà Néill or nic Aonghusa.
The feminine form 'nÃ' or nic, lost in English, means daughter of - it results in a séimhiú (softening/lenition) in the spelling of the last name if it starts with any letter apart from N, L and R - son of Murphy is not subject to lenition and is Ó Murchú (pronounced oh murr-uh-khu) while daughter of Murphy is nà Mhurchú (pronounced nee wurr-uh-khu).
You are basically giving a girl an Anglicised version of the male surname.