“Why did you leave, and why are you coming back?” Simon Knight fizzles with delight as he tells the story of how he and Heidi Dennison were grilled by the student council during their interview for the joint headship of Frank Wise School.

“We had about 35, 40 minutes with the pupils interviewing us. The two best questions, certainly from my mind, were one student asking us collectively whether or not we ever argued, which is really important from a joint headship point of view, as if there’s some sort of marriage. But the other one was brilliant, because obviously I worked here previously – one of the students, she just looked me straight in the eye and said, ‘Why did you leave, and why are you coming back?’ I just thought that was superb. That is a brilliant question.”

Pitching the answer at the right level was a challenge, recalls Knight. Members of the student council at this special school range from 5 to 19 in age, all with different communicative capabilities. And he had to make sure he was also addressing the governors and teacher representatives.

The answer – by the by – is that he left to gain more experience – and with no intention of coming back. He’d taught at the Banbury special school, which has a long history of top-grade Ofsted judgments, for 18 years – from teenage volunteer to teaching assistant, to trained teacher and all the way up to deputy head.

“When everything ended, it was very much Simon leaving,” confirms Knight’s co-head Dennison, who has had an almost identical trajectory – at the same school. “We grow our own at Frank Wise,” she says, “and we have to be quite careful that we’re not too insular, because it is a very successful school, it’s a fabulous place to work.”

Guarding against insularity is one reason it’s been so great to have Knights go out into the wider world of education, she says. “To have somebody come back and say that this really is special, you are really doing quite a phenomenal job, is very different coming from Simon.”

You’ll see more kids blue-lighted into hospital because the nurse isn’t in school

Knight spent his two years away, first as director of education for the National Education Trust, and then as director of Whole School SEND, which made him reflect on his own abilities. “In some ways, moving beyond the school and the opportunities that I had, enabled me to realise that maybe I could do the job that I didn’t think I could do.”

Both Dennison and Knight, however, felt the shoes of their predecessors were too big to step into. “We’ve both been blessed, and I think in some ways, it’s fair to say, cursed by having worked for two extraordinary headteachers,” says Knight. “And you kind of look at them and just think, ‘I could never do that.’ But they both started somewhere. And when you spend time talking to people about school leadership, you realise that everyone started somewhere, and therefore it’s okay maybe not to have all the answers straightaway.”

The pair had already established their compatibility working as joint deputy heads for nine years. “We know each other’s strengths. We know where to scoop the other one up and support each other in different ways,” says Dennison.

So they pitched the idea of a job-share to the governors, slipping in some research and case studies. To convince them financially, they proposed moving from two deputy heads to one and adjusting the headteacher salaries so the cost to the school was no greater overall. Knight also continues to advise Whole School SEND one day a week, with the school benefiting from the income that generates.

Why should our class staff have to compromise on the amount of work they do in a day, if we don’t as well?

“The skill sets that are required to be a really effective head, they’re actually absolutely extraordinary,” adds Knight. “And because this is a school that has been on a long journey of sustained success, I think both of us felt that each of us in isolation wouldn’t necessarily be the complete package, but that between us we would have sufficient capabilities and sufficient qualities that we could maintain the momentum.”

Dennison gets a bit of a rabbit-in-the-headlights look in her eyes when I use the term “flexible working” to describe what they do, and is careful to flag the children’s need for consistency.

“I don’t think flexible is something we’re very good on, but the part-time is something we would be aiming for. I think our ability to be flexible is somewhat limited by the fact that we do need people to be here to ensure the children are safe, and obviously to be learning.”

There is more demand for part-time work than they are able to offer, admits Dennison, who has set the limit at one per class team (which is one teacher and three classroom support officers), meaning over a quarter of staff are doing job-shares. “It’s a careful balance,” she explains, “between doing as much as we possibly can for as many people as we possibly can, balanced with the children’s need for consistency and to be able to anticipate who is in on different days.

They don’t use supply teachers to cover staff absences, as they’ve found them “potentially more destabilising and stressful” – both for the kids as well as the TAs, who know the children and can usually lead lessons “to an exemplary standard,” she says, confidently. “It was actually adding layers that were not only financially costly but really ineffective.”

This does mean that everyone has to pitch in for cover sometimes. “There was a real possibility of me going with one of our classes to the secondary school today to do PE. Very much not dressed for the occasion,” laughs Knight, gesturing to his shirt and trousers. “And I was quite relieved when the school rang up to cancel because it’s supposed to be outside and it was pouring down with rain. But it’s those sorts of gestures that are really important because why should our class staff have to compromise on the amount of work they do in a day, if we don’t as well?”

Frank Wise is feeling the funding squeeze and pupil-to-teacher ratios are creeping up – classes used to be around eight pupils, and they’re now generally nine or ten, but they’re still only covering their costs. Like mainstream schools, they’ve been hit by increases in national insurance, pension contributions, unfunded pay rises, the apprenticeship levy and utility inflation. It’s complicated, says Knight, because “for us staff isn’t just quality of education, it’s about safety and dignity as well, because we’ve got medical and healthcare needs.”

The school has also been affected by austerity in wider ways – their previously full-time nurse is now only with them four days a week – a move which might not actually be a cost-saver, suggests Knight.

For example, if a child’s having a seizure and the school has used the emergency medication protocol, but things aren’t going the way they’re expecting, they can’t just wait and see, like a trained nurse might. “If things are going wrong we make a 999 call immediately,” he explains, “because we can’t make clinical decisions. So you’ll see more kids blue-lighted into hospital because that nurse isn’t in school, and the cost of that nurse being in school is about £40 per pupil, per year.”

In such a context, it’s not surprising that the pair are glad to share the burden of decision-making.

“Knowing at the end of the day there’s two of you that can be held accountable, and are choosing to be accountable,” says Knight, “means it’s much easier to put those things to bed in a way that I don’t think it would have been if it was me on my own.”

“The joint headship for me, was the fundamental difference between it being an appealing prospect and something I really wouldn’t be interested in taking on. It was that significant a difference,” agrees Dennison.