Finn's a big +1 on this whole thing. Although, he would bring up that it appears the family moved around a lot and suggest it could be at a particular childhood home of the "older brother" or "younger sister."

But it's really just a suggestion to cover their bases. His thoughts are aligned with Sabriel's on this.

EDIT: In light of what Clara & co. discovered, Finn's first stop is also going to be the train station.