We went through a few iterations of letter/ statement design because they had to go through third party software to have the individual customer's data inputted and these two were the most recent versions that were being A/B tested when I left. Statement letters are notoriously confusing, and having done battle with several different energy suppliers over the years, I switched to OVO myself, and I wanted to make sure that I understood exactly what was going on in my statement when it came through the door so I tried to make it as simple and clear as possible with a really basic overview on the front page and then more details and information on subsequent pages. I prefer the top version personally because the first glance is so basic and straight forward. I have no idea which version they ended up going with, as it wasn't live before I left, and I'm no longer an OVO customer.