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
mr duncan » _ duncan, mr dundas

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