Definitely seems that something is not right here with both of your connections @robjg63 & @Kowalski.
@robjg63 - I can see our tech lead has looked into your case and has logged a fault with Chorus. It looks like they've decided to come out and replace the ONT tomorrow. Fingers crossed this fixes the issue.
@Kowalski - We believe you and @robjg63's connection are both being affected by the same issue. Pending how @robjg63's site visit from Chorus goes tomorrow we'd like to look into logging a fault on your connection with Chorus also. We'll be in touch via email to let you know what's going on shortly.
Looking forward to getting this sorted!