After a bit of advice here if i may, we currently have a Sophos web appliance deployed as an explicit proxy however with BYOD gaining traction I was looking at switching to transparent mode.

We currently have a cisco 2911 router however its configured and managed by our ISP and all config changes have to be hand written signed and faxed across. So why question is this exactly what changes do I need them to make and what information do I need back from them?

The appliance supports WCCP which i have no experince with but the available setting on the appliance look simple enough. Is its as straight foward as asking our ISP to setup L2 WCCP on the router to forward port 80 & 443 traffic to our internal proxy and to let us know the group password to put in the appliance?