The 700-pupil college - which charges fees of up to £49,000 ($97,000) a year for tuition and boarding – is still partly housed in a network of its original medieval buildings,and serves as a key pipeline into Oxbridge.It counts dozens of politicians,archbishops and six chancellors among its alumni,including British prime minister Rishi Sunak. The move to allow girls being described as a possible death knell for elite British male-only schools,leaving its main rival Eton and just a handful of others (Harrow,Radley,Sherborne) to continue the all-boys tradition.

“This is a school where you go into the chapel,and you know that boys have been kicking the back of the pews for more than 600 years,” Stone says. “We need to be really aware that girls have to be welcomed as full citizens. It’s got to be their place,as much as it is the boys’.”

After spending almost a decade at Queenwood,she is diplomatic when quizzed on co-education versus single-sex schools. Although more Australian private boys schools are coming under pressure to switch to co-ed,Stone believes girls schools are far more likely to resist change. “There’s a more obvious case for girls schools to stay girls schools. There are particular advantages to single-sex education,for both,and each come with their own particular problems.”

“I used to think the relatively high number of single-sex schools in Australia – and NSW – was just kind of normal. But girls and boys-only schools have virtually disappeared in other states and territories except for NSW,and the same phenomenon is happening in the UK.” Of the 68 independent single-sex schools in NSW,just over half are all-boys.

For the British school,the decision to embrace co-ed was made after more than a century of deliberation over the matter.In an interview in 2021,former head Tim Hands said:“We can no longer see any good reason not to allow girls access to Winchester’s unique approach to learning.”

As our meal arrives,the conversation shifts back to her decision to leave law for school teaching. I ask what it was it about teachingmaths – in particular – that she was drawn to? “Because that’s the subject kids are most phobic of,” she explains.

“If a child finishes year 4 and 5,and they don’t really understand fractions,then that’s it. It becomes this huge black hole. It can then affect their ability to grasp higher level maths concepts – like algebra and calculus – if a child falls behind.This is not a music class they have once a week,it is maths,they are doing it every day. Their self-esteem can fall through the floor.”

“Helping turn that around,it has this knock-on effect for their confidence,relationships,and how they see themselves,” she says,adding that quick recall of times tables in primary years is also essential. “Without it there is a massive brake on learning because it takes up so much working memory that students can’t concentrate on harder stuff,like factorising a quadratic in year 10.”

After moving into deputy and principal roles,Stone has continued to teach maths,mostly year 7 and 8 maths classes,but occasionally older years too.

“Teachers are often nervous about letting others observe their practice and provide professional criticism. You can feel very exposed. I’m no different – which is why I need to push myself to do it too.”

One of the most significant changes moving to a private British school will be adapting to boarding life and much longer school hours,she says. ″⁣The day starts at 8:30am and three days a week stretches until 6pm. Lessons are held on Saturdays,with sport in the afternoons and two hours of supervised homework at night.″⁣ After chapel on Sunday morning,there is free time from around midday until Monday morning. This is a boarding school pattern that doesn’t exist in Australia,she says,“except for maybe at Geelong Grammar. There’s a small minority of teachers who don’t live on campus,but pretty much everyone’s in school housing,it’s all fully integrated.”

But previous experience working in British schools has eased the pressure of taking on a principal role in a new system. In 2008,after three years as a maths teacher at Barker,she moved her young family to south-east England where she spent a few years teaching maths at Winchester,then became vice principal of another top school,Cheltenham Ladies College,just south of Birmingham.

“It’s partly completely implausible that I would have ended up the head of a school like Winchester. You know,how has this Australian woman ... ended upthere? But I think my experience in both single-sex and co-ed schools,in law,and in school management in the UK,really helped.”

Teaching,and working as a school deputy and principal,has become increasingly complex in the two decades since she took her first maths class,she says. “Compare the job of a teacher 40 or 50 years ago to now. It’s been massively expanded. And it’s not just extra workload pressures that are often cited,like playground duty,excursions,administration.

“There’s been regulatory changes,the rise of social media,changes to parental expectations. And these huge expectations to respond to mental health issues,and problems of school refusal. The procedural burdens for managing student disciplinary issues are unbelievable. It chews up so much time,attention and resources. It’s changed the job. We used to be much more robust with kids. We used to be more robust with parents.”

While principal at Queenwood,she decided to ban laptops and iPads in the school until year 9,and a few years ago introduced a program where all 900 students have a mandatory 20 minutes of reading before the school day starts in a bid to counteract the decline in reading for pleasure among device-devoted students. “It’s a counter-cultural technology policy. We delay devices as long as possible.”

The 50-year-old’s no-nonsense approach seems,at least in part,influenced by her own education at eastern suburbs private girls school Ascham. She graduated in 1990 while it was under the famously strict control of redoubtable headmistress Rowena Danziger. She admired Danziger’s approach,she says,because “she knew what she stood for”.

“She is a force of nature,and I have no doubt I imbibed a model of school leadership under her. You knew what you stood for,articulated that and held firm. It’s so easy to go with the zeitgeist. It’s attractive to have someone who knows what they believe.”

In the decades since,Stone says “curriculum expectations have expanded massively”, despite no change to school hours or the number of school days in a year. “We have loaded up the responsibility on schools to teach students about so many things – from nutrition,drugs,sexual consent,safe driving,the list goes on. It is shifting the burden of what is expected of teachers so substantially.”

She believes one reason for the increased demands on schools is because they are one of the few community institutions left. “And so that’s where people are consistently turning.”

It is a topic she spoke about in detail in June while on a panel for the Ramsay Centre for Western Civilisation,where she has also served as a board member for the past six years. “If schools operated 24/7,I might have a shot at pulling it off. But there’s no time in the school day. And there’s a big cost,including time lost to the things that we know we can – and should teach – like reading,and writing well.”

I ask her if she can ever imagine returning to the legal profession or to universities as a lecturer or an academic.

“Actually,for a while I was doing stamp duties law,which sounds dry,but it’s actually incredibly interesting. I really enjoyed it. It’s like cracking a puzzle. But at the end of the day,the best I could say in terms of the good that I’d done for the world was that maybe I made the economy slightly more efficient. And that felt like it was a very remote good.”

“The bottom line in teaching is the good – the higher purpose – they have names,and they come up and talk to you. Even when you have your difficult spells,your dry spells,never do you wonder whether what you are doing is worthwhile.”

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