Download Sophos Anti Virus (SAV) Classic Edition for Mac (Non-Home/Cloud) - Free

When Sophos AntiVirus first launched on Mac, it provided a free version for home users which contained the same feature set including Adware / Threat Detection which is used in the Enterprise Version.

However over time, Sophos quietly withdraw this when their new Sophos Home product launched which is Cloud based. Sadly on Sophos Home, a lot of features which were provided for free were withdrawn and pushed onto a premium home plan like for example:

You can still download the 'Classic' version, but it's download is mostly hidden as Sophos wish to push people into their cloud offerings and up-sell features. The Classic version is still receiving updates all the time, however the installer hasn't been updated to support High Sierra without workarounds detailed here. Once installed, it will update and be fully compatible.

To get started, you can download Sophos Anti Virus 'Classic' for Mac from the following URL:
Sophos Anti Virus Classic for Mac

During installation, you will likely get the following error:
The Installer Cannot Continue - The "Sophos Installer Components" folder is missing required files. View install.log for more information.

To resolve that, you can use the workaround detailed here to resolve it:
MacOS 10.12 Gatekeeper Can Cause Installation Failure

Complete this on as many Mac's as you need

That's all there is to it, enjoy Enterprise level security on your Mac's for free.