Unfortunately thats not helped my case much. I have a webcam pointing at (what is now) their router right next to the ONT, merrily going red every 5 minutes this afternoon, but the line is clean their end whenever I happen to call and they're not interested in videos / pics...

Presumably openreach have a log of PON Flaps on the OLT. Not sure why they are unable to pull them.

one option and one which make you cry into your crunchy nut cornflakes. Is to put the sky hub router back on, it will report back the connection losses and then sky will care a bit more.

Ask Sky for a deadlock letter and go to their ADR scheme, there are lights on the ONT for a reason