My NBN was playing up until I discovered the phone cable had half worked its way out of the wall plug
Pushing it back in fixed every thing, well almost

Watching videos on YouTube is not as good as it used to be. Every few seconds it stops for a faction of a second, just enough to be annoying
I've tried different screen resolutions, doesn't make much difference. It's currently on 720

Any ideas why this is happening and how to fix it?

Ken