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

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