What notifications?
Are other functions on the iPhone OK on the Wi-Fi - email, web browsing, maps, apps?
Does she get notifications if on mobile data? On other Wi-Fi in shops, outside cafes etc. ?
------------------------------------------------------------------------------------------------------------------------------
I know a bit about Wi-Fi, Telecoms, and TV as I used to do it for a living but I'm not perfect so don't beat me up... If you make things you make mistakes!