Wouldn't bank on Boldon or Silksworth being relegated as I'm almost 99.9% certain that those teams were told at start of year that there'll be no relation due to houghton demise. The clubs in question specially have stated this as the reason for not engaging overseas in several occasions over this year.
If they have been told that in any capacity by league then there's not a chance the league would be able to relegate them without an almighty uproar.
As someone pointed out if leadgte were to come over to this side of pyramid would they not have to start at bottom? I.e. NEDCL or are NEDCL still not a fully fledged member as they didn't want to be governed by league cricket conference? That may have changed mind so be good to know current state of play.
Lots of grey areas and no freely available docs to confirm to anyone so very much just hearsay.