Perhaps you should try some spelling variations:
"john dunning sir" » "john jennings sir", "john dennis sir", "john dunning jr", "john dunning mr", "john dunning eric"
"john dunton smith" » "john brunton smith", "john sutton smith", "john fenton smith"
"john duncan sir" » "john duncan i", "john duncan sarah"

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