Mrs Treadell described herself to a class of years 5 and 6 as the first woman "after an illustrious line of gentlemen" to hold the high-ranking diplomatic post since taking over the role in June.
It was third time lucky for Clutha-Southland MP Mr English - Catholic, father of six and former teacher - who twice before was meant to visit the school, once when he was acting prime minister.
Pupils provided, perhaps unintended, comedy when asked to identify the prominent politician.
"He's from Wellington?" one ventured.
However, the class soon showed they were up with current events, quickly pegging Mr English as their local MP and second-in-command to John Key.
The pairing of the diplomat and politician arose from a conversation between Mr English and Mrs Treadell in the capital.
"Bill said I should make a visit to Queenstown in the early part of my time [as commissioner] - firstly to understand all of New Zealand outside of Auckland and Wellington, and secondly because of the number of British tourists who visit and live here.
"I came here to get to know New Zealand and all the different dynamics," Mrs Treadell said.
Born in Malaysia to Cantonese and French-Dutch parents, she is also the Governor of Pitcairn.
Before taking her latest post, she was British deputy high commissioner to India and has been posted in Pakistan and Malaysia. She is the first woman of Asian lineage to be a British high commissioner.
Mr English and Mrs Treadell were guided by school "ambassadors" year 7 and 8 pupils Maddy Holmes, Georgia O'Malley and Maggie Burns.
The High Commissioner asked the trio what they were considering career-wise. Television news presenter/reporter, dancer/writer and accountant/Silver Ferns netballer were the girls' respective answers.
Her advice for the girls was to "believe in yourself and have confidence, but I would qualify that by saying that begins with understanding yourself - self-awareness is your starting point".
School principal Trisch Inder said new people were always shown around the school by older pupils because they gave visitors "an honest view ... and because they love it".
