They don’t plonk 2 who get relegated into the North and 2 the South. If all 4 relegated teams are northern they will restructure NLN and place teams more southern already in NLN into NLS. There are quite a few teams in there who are far more southern than us, so it’s not going to happen with us in NLS.
In fact, 14 of the teams in NLN are further south, so it’s impossible to even contemplate.