On Thursday evening seven party leaders will meet in an ITV studio for the much-anticipated general election debate. Some of them are - it's fair to say - rather less well known than others. Many viewers - in England, at least - will not know all that much about Leanne Wood, the Plaid Cymru leader. So, on Profile this week, Mark Coles has been finding out what makes her tick.

Producer: Gemma Newby.