Have any fellow Brits been following the series "That'll Teach 'Em" over the last few weeks?

The producers took a bunch of present-day students (last year of school, so aged about 16) and put them through 4 weeks of school as it would have been in a typical British Secondary Modern school of the 1960s to see how they'd cope with the different subject, different exams, different discipline, etc.

In the last episode this week the girls took their domestic science exam, and mixed in with the cookery was a test on how to wire a plug.

It was only on-screen for a brief moment, but did anybody else notice the mistake?