Hi Mjk,
Hope you are well.
Have you considered Sophos UTM?
The Sophos UTM:
Is listed on the UK Safer Internet Centre for Appropriate Filtering for Education Settings.
Aligns with recommendations from Ofsted and the Prevent directive
complies with guidelines set out in the Keeping Children Safe in Education publication (2016)
Main other points are:
All internet based traffic is scanned for viruses - Sophos and Avira
Multi-layered Intrusion Prevention and VPN access Age appropriate filtering for pupils and the ability to vary filtering policies based on the role of staff - integrates with your local AD
Gives the School complete control of URL filtering to permit or deny access to specific contentIt provides the ability to report inappropriate content accessed or blocked
The solution offers clear historical information on the websites visited by staff, pupils and visitors
Sophos Labs collect, correlate and analyse data to provide the best protection for every Sophos customer containing 35 million+ sites
Sophos work in partnership with the Internet Watch Foundation which ensures maintenance of a list of known illegal, inappropriate and criminal sites to block is up to date.
96 different web categories available for selection within the Web Filter including Criminal and Counter Terrorism which forms part of the Prevent directive
Unlike other solutions the Sophos UTM pricing model is based on the number of devices rather than the number of users.
If you would like further information, please let me know.