She acted in Alun Owen's play, "A Little Winter Love," at the Theatre Royal in Stratford East, England with Rachel Herbert, Paul Maxwell, Kenneth Farrington, David McKail, Roger Hammond, and Celia Hewitt in the cast. Garry O'Connor was director.
The famous imitated line of Michael Caine by Steve Coogan (in The Trip), "She was only sixteen years old!" which Caine never actually said, refers to Petra's character... although she was in her early-twenties playing younger in Get Carter.