In 2007, the Hewitsons were asked to take on the NT's biggest remote area school, the bilingual, government-run Shepherdson College at Elcho Island's Galiwinku community in Arnhem Land.
In February 2009 the Hewitsons were on the scrapheap - after being booted off Elcho Island.
The Hewitsons say they paid the price for challenging local Aborigines, the NT Department of Education and Training, and the bilingual system, which treats English as a second language.
"I think they think English is evil," George Hewitson says. "The notion is promoted that if you learn English, you lose your culture."
The Hewitsons also uncovered what they believe to be fraud, with 700 students enrolled and supposedly attending Shepherdson but, at best, just 220 turning up each year.
There were 36 teachers at Shepherdson - about the right number for a 700-student school - but with only 200 children, the Hewitsons raised concerns that it was overstaffed.
The Hewitsons believe attendance figures were distorted to maintain high numbers of teachers and to attract better funding.
The Hewitsons believe they uncovered more than the NT Government could handle -
70 per cent of students from years 7 to 12 could not read beyond early year levels;
50 per cent of years 7 to 12 students could not recognise letters from the alphabet;
and of 45 students from years 7 to 10 who sat an equivalent year 7 writing test, only four could write more than one sentence.
The Hewitsons claim children with no literacy were being scored bare minimum 10 out of 20 passes for tests that should have been failed.
"The attitude was that it was better to lie and for people to think you were doing well than to tell the truth," George Hewitson says.
"I proposed that there should be an indigenous literacy test, to prove to me that bilingual was working," George Hewitson says.
"Our bilingual teachers had a fit about this. They would argue that you learn your own language and at about grade 5 you swap over, and then English becomes really easy. It's crap."
Although he is not involved in running the school, Elcho elder Djiniyini Gondarra strongly disagrees with this thinking.
"They wanted us to stop speaking our mother tongue and act like a white man. You cannot expect everyone will be like that. They stopped bilingual education, they would not allow it. He was a hard man to talk to and convince. His understanding is that you can shape a Yolngu person and the only way is to teach English.
"I don't tell myself to stop speaking my own mother or father tongue. When I was growing up, I was hungry for education and I wanted to learn. I knew English could open up a world for me. But for me to understand English, I had to go back to my own language, to really understand the intellectual language."
And this, at its heart, is the bilingual argument.
According to George Hewitson, the Elcho boys told him they were desperate to shake off their illiteracy.
He says they feared off-island excursions because they couldn't read street signs.
It confounded the Hewitsons that some Aboriginal parents, taught by missionaries and literate in English, saw little value in their children learning the language.
George Hewitson says Shepherdson is in the grip of certain teachers, black and white, who have adopted a view that the proper approach, nowadays, is to support Aboriginal languages ahead of English.
This is partly borne of guilty knowledge that old-time missionaries frowned on Aboriginal languages and, in some places, extinguished them.
The Hewitsons think it's simple: children should speak their own language at home and learn English at school.
The Elcho Aborigines are fighting what they see as language imperialism.
Complaints about the Hewitsons led to an education department audit of the school in July last year.
Mr Hewitson went to see the department. "They started talking about trauma and offering us counselling. We were told we'd get paid leave, but that we could relinquish our positions."
By September, 13 members of the school council had written a petition to the department saying they didn't want the Hewitsons, now off the island, to come back.
George Hewitson went from being one of the equal highest paid principals in the NT - earning almost $160,000 - to being offered a job as a truancy officer in the town camps of Darwin.
Robyn Hewitson, a secondary teacher, was offered a primary school position in Darwin.
"We have been betrayed because the Government is frightened of Yolngu people and they don't really want to close the gap," George Hewitson says.
"I think they didn't want to take on some influential Aboriginal people in the community, which is gutless."
Voices of dissent, Paul Toohey, The Australian, 26 February 2009 : Read more : http://www.theaustralian.com.au/news/voices-of-dissent/story-e6frg6po-1111118964289