TC55 - Tethering

Hi wondering if anyone in this wise community can help me.  I have a number of TC55's which have roaming SIM cards so they work across all UK mobile networks.  The cost for data is relatively high, but we are not pushing that much data through and to have access to all networks is a big plus.

 

We are playing with stage now to restrict which apps can be used and which are loaded on start-up.  Also to set APN / Wifi access.

 

I've looked everywhere but I can't seem to find a way to stop a user from enabling tethering.  I can switch off access to some of these menus but thing is I do want users to be able to connect to local Wifi and potentially pair on bluetooth.  And switching off menu options restricts access to these important settings.

 

Any ideas?  Pretty please.

 

James