I can't remember ever hearing anyone ever mention a single problem with the Westley single trigger.

If that trigger system was known to have any problems back in the day, you can bet that WR would not still be fitting them to the DR's they're building these days.

I really prefer two triggers on a DR, but have owned and hunted with 3 single trigger, large, medium, and small bore DR's over many years.

None of these doubles were/are anywhere near the quality of Westley Richards guns, and none ever had any issues regarding their single trigger reliability.