Bad earth? Reg rec? The buzzing sound is coming from the low beam relay.

I had this issue previously and it sorted itself when I took all the relays and block connectors apart and cleaned them. At that time I noticed that the connector from the stator to the reg/rec had melted (common fault on these apparently). So I replaced that block connector. No issues since then!

Last week I started the bike and left it running to keep the battery charged up as I haven’t been using it that much. Went back outside after a while and she was dead, plenty of fuel left. Key still in the “on” position. I couldn’t get anything out of it so assumed the battery ran down? Charger won’t charge the battery, says it’s full. The battery was replaced the last time I had this issue, only a few months ago.

I have noticed another supposedly common issue with these, corrosion of an earth wire under the left side fairing. I’m awaiting to reroute that earth.

Any other ideas?