Helping a relative who is about to register their baby's name. She is not married but in a long term happy relationship with the father.
They have decided on first name and second name, and also know they want the child to use the father's surname. It's a lovely sounding name too, if that makes a difference - three syllables, so not particularly short.
They were wondering whether to add the mother's surname in the mix too. But they don't want a double barrel name as it will be too long (both surnames are longish, and together feel tricky to spell- the child would spend their life spelling it down phones!). But it might be nice to have both, and also mother's surname somewhere in there since they are not married (although I know it probably doesn't make a difference, legally, since of course there's a birth certificate etc).
Could the mother's surname appear as a third name? So not be part of the "surname" ? If that makes sense. I am not sure I am explaining it correctly. Thank you all!