Perhaps you should try some spelling variations:
"a duncan sarah" » "a duncan gray", "a duncan shaw", "ra duncan sarah", "_ duncan sarah", "j duncan sarah"
"bruce duncan smith" » "bruce duncan scott"
"bruce duncan sir" » "bruce duncan i"
"a duncan adam" » "ra duncan adam", "_ duncan adam", "j duncan adam"

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (((("a duncan sarah") OR ("a duncan adam"))) OR ((("bruce duncan smith") OR ("bruce duncan sir")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"a duncan sarah\") OR (\"a duncan adam\"))) or (((\"bruce duncan smith\") or (\"bruce duncan sir\"))))".
• Removing quotes may allow a broader search: (((( a duncan sarah ) OR ( a duncan adam ))) or ((( bruce duncan smith ) or ( bruce duncan sir )))).
• Adding a wildcard symbol may retrieve word variants: (((("a duncan sarah") OR ("a duncan adam"))) or ((("bruce duncan smith") or ("bruce duncan sir"))))*.