Welcome to the Community @GeoffS
For customers experiencing any issues with their NBN service, we recommend the best thing to do first is check if there's an outage on the NBN network.
We have created this article that can guide you on How to Check for NBN Network Outage.
This will allow you to access more detailed information regarding the cause of the outage.
In your case, we've escalated the case to our Engineering team to investigate a possible fault within the NBN network or equipment issue that causes the dropouts.
An assigned Engineer will be in touch with you via SMS or phone call as soon as an update becomes available.
BasilDV
