Well you could photograph the screen and cover up the personal stuff if your friend doesn't want to show it. I put it down to the caper of meter reading, estimates, corrections and increasing prices. Smartmeter and a direct debit plan should take out any wandering of the bill with estimates / meter reading errors. The plan would be adjusted by the company as required.

The old fashioned way of doing stuff with postal bills, red reminders, cheques, estimates is all a bit fraught and you pay more as I said because the energy company covers its overheads of people with erratic payments on those people that could pay erratically.