Perhaps you should try some spelling variations:
"ian duncan sarah" » "ian duncan adam", "ian duncan gray", "brian duncan sarah", "jon duncan sarah", "innes duncan sarah"
"a duncan smith" » "a duncan scott", "ra duncan smith", "j duncan smith", "m duncan smith"
"_ duncan smith" » "_ duncan scott", "_ dunciad smith"
"a duncan sir" » "a duncan i", "ra duncan sir", "j duncan sir", "m duncan sir"
"ian duncan shaw" » "brian duncan shaw", "jon duncan shaw", "innes duncan shaw"

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 smith") OR ("_ duncan smith"))) OR ("a duncan sir"))) OR ((("ian duncan sarah") OR ("ian duncan shaw")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((((\"a duncan smith\") OR (\"_ duncan smith\"))) or (\"a duncan sir\"))) or (((\"ian duncan sarah\") or (\"ian duncan shaw\"))))".
• Removing quotes may allow a broader search: (((((( a duncan smith ) OR ( _ duncan smith ))) or ( a duncan sir ))) or ((( ian duncan sarah ) or ( ian duncan shaw )))).
• Adding a wildcard symbol may retrieve word variants: (((((("a duncan smith") OR ("_ duncan smith"))) or ("a duncan sir"))) or ((("ian duncan sarah") or ("ian duncan shaw"))))*.