It should be based on the Aussie system, adopted by RL SuperLeague.
All of these as one-off matches (not two legs):
a) 3rd v 4th - winner to Wembley final, loser gets second chance in the second round match below
b) 5th v 6th - winner to second round, loser out
c) second round: winner to Wembley final, loser out
Not only is that fairer, but there is motivation for play off sides to finish as high as possible. Why is that so difficult?
Don't like the idea of team getting a second chance. Makes a mockery of the whole thing. It's a no from me.