Have you done Nigella's version? I haven't even attempted crackling for about 15 year.
Nigella says to take the rind off and cook separately. Basically you cook for in the oven for 45 minutes, on a rack over a roasting tray (so it's not sat in its own juices).
I guess this is on the same temperature as the joint?
Is it as simple as that or have I misunderstood?