On the main app loading page, Parental control and Adguard home show as Enable / Set up Now and are grey even though the applications are running on the device (brume 2) selecting each option and returning to the landing page forces the app to realise that the plugins are actually configured and running. Closing the app and reloading will again suggest that both the plugins are no longer enabled.
Seems to be working correctly now. Unsure if there was a silent app update as I am still on 2.6.3 or if it was a case of rebooting the router. Anyway, problem solved.
I have noticed that when I go to the plugins tab the app checks and see if the services are running and eventually reports correctly. When I visit the plugins page and go back to the app homepage I also see that network storage becomes visible too but prior to clicking on the plugins page, the network storage icon and status indication is missing.