It is the largest saving identified by any of the 58 heads who responded to the TES survey.
But it is not the result of radical reform. Dr Wilkes has done it with only minor changes to the school's staffing structure, including the employment of additional support staff to provide teachers with administrative support.
The head of careers will become a non-teaching post, while four curriculum posts connected to courses the school no longer offers will be scrapped.
The only new post is a gifted and talented co-ordinator.
There are winners and losers among heads of department, with changes to the size of the payments they receive determined by the size of the department and the contribution it makes to the school.
Dr Wilkes is adamant the school was right to reject suggestions that pastoral posts should be given to non-teaching staff.
"I think you have to relate the pastoral to the educational. Our heads of year are very much focused on pupil outcomes. I would be very concerned about removing salary from any of my staff where they qualified for a TLR."
Like a number of other headteachers who responded to the survey, Dr Wilkes questions whether there was a real need for every school to overhaul its staffing structure.
He said: "I don't see it making a great deal of difference. I remain to be convinced that the amount of time spent on it will be time well spent."
Even the expected savings may never materialise. Until 2008, the school will have to continue to pay management allowances at their current levels to all staff worse off as a result of the changes.
From September, when the new structure will be introduced, until the end of that safeguarding period, the staffing budget will be pound;15,000 higher than at present.
By the time the savings come through, Queen Elizabeth may already have spent them.
Dr Wilkes is currently considering employing additional games coaches to support his PE teachers.