The paternity of John the Banker or Cashier was in fact before the Lord Lyon King of Arms recently regarding who was the head of the Breadalbane Campbells. Some sources state Colin died without issue and others give John as a son. I'm uncertain if the issue was ever resolved. Either Lachlan Campbell, John's heir, or Huba Campbell, who is otherwise heir of the family, would be an earl. Here is an online reference that addresses the issue of John's parentage: http://archiver.rootsweb.ancestry.com/th/read/CAMPBELL/2001-02/0981125769