Perhaps you should try some spelling variations:
duncan sir » duncan i, duncan sarah
jon duncan » john duncan, j duncan, colin duncan
ian duncan » brian duncan, a duncan, innes duncan
ra duncan » _ duncan, mr duncan, j duncan

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: (( ra duncan sir ) OR ( ((jon duncan) OR (ian duncan)) smith ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( ra duncan sir ) or ( ((jon duncan) OR (ian duncan)) smith ))*".