Hi @davidjhunt ,
This may not be related on settings Netgear Nighthawk xr700 but you may find this thread helpful on how to configure a 3rd party modem/router on TPG-NBN HFC.
Please see link below.
Alternate router to use on HFC
Hi , has anyone successfully connect a Netgear XR700 router to the NBN HFC without needing to use the modem supplied by TPG.