It's hard to determine exactly how much Quality each team has what quality, I suppose your lower level teams like L1-L4 to example are your local pub team sunday leagues before getting onto county leagues and then minor regional leagues before you reach Northern/Southern/Isthmian leagues then conference North/South/Premier before football league.

Premier League would be mixed levels since Man Utd/Man City and Chelsea would be above everyone else, Arsenal and Spurs a level behind with Liverpool and Everton a further level behind those.