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

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