With EES you can take advantage of the Home Use Program (HUP), which is a benefit of the Microsoft Software Assurance coverage included with the EES subscription.
It is important to note that with the HUP, only Microsoft Office is available - nothing else. Whereas the Work at Home (WAH) rights allow you to use a variety of applications for work purposes only (including Microsoft Office) - it is only under the Home Use Program that you can use Microsoft Office for non-work purposes.
Furthermore, in the EES FAQ it says ‘You are not permitted to provide licensed product with the same title to any individual faculty or staff member using both HUP and WAH.’ - so you cannot provide Microsoft Office to faculty and staff under both programs - not that I can see why you would want to anyway.
Office 2010 under the Home Use Program (HUP) is priced at £8.95 and can be ordered ad-hoc via http://www.microsofthup.com/hupuk/home.aspx?culture=en-GB. Prior to ordering you will need to activate the HUP benefit on your Microsoft eAgreement and follow the instructions to receive the specific HUP code for your school, which your staff will need to enter when ordering.