Pardon The Expression (Ep. 12) The Brain Drain (1965)

Plot: (From Corriepedia )
This IQ of the Dobson and Hawks' salesgirls leaves much to be desired. And the girls are just not interested in Mr Swindley's proposition of night school current affairs. But Swindley finds the answer - catch them before they leave school. Swindley tries to induce the Brookfield High School girls to join Dobson and Hawks when he attends their careers day (or "slave auction" as Headmistress Miss Buxton refers to it) but the attractions of the store cannot compete with the multinational companies also in attendance and Swindley only manages to bag one recruit - a bright girl called Mary. This however is one more than expected so Mr Parbold is well pleased with the result.