Two fixed-term, one-year contracts will be replaced by one contract and changes are to be made to the administration team at the 880-pupil school. It opted out of local authority control nearly five years ago, and overspent on its Pounds 2.6 million budget last year.
Governors have told staff they accepted full responsibility for the situation and that they had not fulfilled their obligations to question advice that had been given them.
They said they were unable to understand why budgeting errors had been made and that the failure to balance the budget in 199596 had been of great concern to them.
In a letter to staff, governors pledged to challenge and question the figures in the recovery budget "which must set the school on the right path for the future".
They have now set up a series of standing committees and said: "Our aim is to regenerate the confidence of the staff in the ability and commitment of the governors to oversee the running of the school.
Problems at the school, where 99 per cent of pupils gain five or more GCSEs at grades A-C, appear to have come to light since the appointment of a new headteacher and a bursar.
The Funding Agency for Schools - which oversees GM finance - is aware of the deficit and a spokesman said: "We are content that the school is addressing the issue in an appropriate way."
Genefer Espejo, headteacher, was confident the debt could be wiped out within two years from within Nonsuch's own resources.
She is in the first year of her post, having moved from a headship in Berkshire, and said staffing had been generous in relation to finances. The school, which is oversubscribed, will be admitting an extra 15 pupils in September, taking its intake up to 150, as well as paring back staffing.
"Clearly I am very confident that we will pull away from this situation very quickly without any additional income from anyone else in terms of loans, " said Mrs Espejo.
A copy of the statement of accounts for the school reveals it suffered a Pounds 500,000 cut in Government grant between 1994 and 1995.