Like others I read on here, when choosing Safeguard under the Broadband icon, switching the toggle from OFF to ON then blocking certain sites and resetting the router, after 2 hours the toggle is back on OFF.
I spoke to Plusnet who sent these instructions:
Locate down the "Left" side - Under "Manage Account" - "Plusnet SafeGuard"
Click Here and follow the on-screen instructions to download the file.
Please Take note of the Serial Key provided - you'll need this for later on.
Open the downloaded file and select "Allow to make changes to device"
Await the installation to complete.
BUT - there is no "Plusnet Safeguard" listed in the "Manage Account" section. It is under the "Broadband" icon/section.