i doubt that there are rules about charging batteries from grid electricity - the issue is what you do with that stored energy. Consuming it in the residential environment is completely OK. But selling it back into the grid, at least via the SEG, apparently isn’t.
Current Eon Next and EDF customer, ex Zog and Symbio. Don't think dual fuel saves money and don't like smart meters. Chronologically Gifted. If I offend let me know by private message, but I’ll continue to express my opinions nonetheless.