The_Right_Honourable_Brit
High Tory
It's most likely stage 6 for the rest of the week. They send out the initial announcement showing drops to stage 5 and 4 afterwards to make it seem not so bad but just slap on permanent stage 6 when the time comes. Don't see why they would otherwise need to go to stage 6 from 21:00 to 05:00 when most people are asleep and not using electricity.
It's so they don't have to burn diesel overnight and allow for the pumped storage schemes to be ready for the next day.