As the non-league structure moves towards a more symmetrical pyramid for season 2020-21 the following promotions and relegations will apply for Season 2019-20:-
Top team automatically promoted to Step 4.
Second placed team will be promoted to Step 4 if one of the 4 highest positioned teams (on a points per game basis) across the 11 most southerly based Step 5 leagues. If not one of the 4 highest positioned teams then the second paced team will have a play-off match against one of the bottom placed Step 4 teams with the winner securing a Step 4 place and the loser to play at Step 5 in 2020-21.
The bottom team will be relegated unless it is one of the two highest positioned teams (on a points per game basis) across the 14 Step 5 leagues.
First Division North and South
Top 4 teams from each division automatically promoted to Step 5. This can probably be defined as top 4 eligible teams.
Bottom 2 teams in each division liable to relegation to Step 7.
With an increase in the number of Step 5 leagues from 2020-21 and a decrease in the number of Step 6 leagues it is likely that the footprints of the Thurlow Nunn League divisions will be slightly changed.