To Kill a Mockingbird:

Sergel's play toured in the UK starting at West Yorkshire Playhouse in Leeds in 2006, and again in 2011 starting at the York Theatre Royal, both productions featuring Duncan Preston as Atticus Finch. The play also opened the 2013 season at Regent's Park Open Air Theatre in London where it played to full houses and starred Robert Sean Leonard as Atticus Finch, his first London appearance in 22 years. The production is returning to the venue to close the 2014 season, prior to a UK Tour.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". Who played Atticus Finch in the UK theater productions of the film in 2006 and 2011?
Duncan Preston