The opera the Crane brothers return from at the beginning is Wagner's 'Parsifal' which has a running time of just over four hours. Together with two intervals of about 25 minutes, this would push it close to five hours. Many opera houses would start this performance at about 7pm, so it would be well past midnight when they arrive back. Yet Daphne and Martin are dressed and wide awake like it's early evening.
In the closing credits, 'bailiff' is misspelt as 'baliff'.