It depends from city to city - Glasgow would shut off earlier vs London.
So technically the solution is devolution of power down to the city level to let them handle the budget. Not possible with Pakistani governance system immaturity.
As far as I am aware from my time in the UK, no Event venue remain open until 1am as is the case in Pakistan. So the power usage in the UK is still hundred fold better controlled than in Pakistan and it still doesn’t “ruin” the economy
London being the exception as Piccadilly Circus stays open 24 hours a day. Glasgow is too far north, better cities to consider would be Manchester, Liverpool, Birmingham, Bristol and Nottingham.
Outside of London, these cities have sn amazing mix of retail and vibrant night life.
Take Islington in London for example, growing up, everything there would be shut by 8/9, nowadays it’s open well into 3am on the weekends.
Manchester is another city that has changed, when I used to visit Manchester from London in the 90’s everything would be shut by 5. It used to be a ghost town.
Nowadays Manchester has a vibrant nightlife, in fact it’s nightlife and party scene is better than even Liverpool and Nottingham.
Overall, I think Pakistan needs to come up with a concrete solution to conserve power without breaking the back of the retailers or damaging consumer confidence.