@JMNathan 

To force Sky router Parental Control on devices connected to Deco mesh you will need to configure Deco mesh run in Access point mode: Switching a Deco to Access Point (AP) Mode

  @Alexandre. That's interesting, but that totally defeats the point of having a mesh system in the first place!

Is it not possible to set global controls on the Deco? I know I can add a profile to block content on certain devices, but then what happens when new devices join the network? Say when my kids have a friend over, would I need to manually add each device to the profile?

  @JMNathan 

At my house I use Deco mesh to provide WiFi coverage, it runs in Access Point mode. Parental controls are set on my ISP router. 

This is unfortunate flaw in Deco parental control design: when new device joins Deco mesh, it runs unrestricted. What's worse, if you have "MAC address randomization" enabled on device, all it takes is disconnect and reconnect device to Deco mesh for it to appear as a new device (with different MAC address).