You can connect an orbi system to the sky router. You might need to change some settings.
Such as (only use one):
1. put the sky in passthrough/modem only mode
2. put the netgears IP address into the sky routers dmz. disable the wifi on the sky router to prevent interference
3. put the netgear into access point mode. It does disable a few features on the orbi and leaves the sky in control of them. I'd again, advise disabling wifi on the sky router.
