Hi Mark,
I clean a few large schools and the price is always different depending on spec.
By the looks of things that is 2 days work for a crew and if I was pricing I would be looking in the region of £900 - £1100 depending on the odds and sods that may be reuired, internal doorways etc...
If your local to me (Hampshire) I am more than willing to help you with a site visit. The county councils can be a bit tedious with Health and Safety, Risk Assessments and Method Statements.
Anyway,
Good luck, Nice one to add to your portfolio.
Trev