Perhaps you should try some spelling variations:
"ian duncan sarah" » "ian duncan adam", "ian duncan gray", "ian duncan shaw", "brian duncan sarah", "jon duncan sarah", "innes duncan sarah"
"a duncan scott" » "a duncan scotus", "ra duncan scott", "_ duncan scott", "j duncan scott"
"a duncan stone" » "a duncan street", "a duncan jane", "a duncan diane", "ra duncan stone", "_ duncan stone", "j duncan stone"

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