Unless things have changed in Oz (which could well be the case, I guess)
(a) if the departure is below landing minima then you have to have enough fuel for a diversion and prudent performance engineering will address that for an emergency situation arising during the takeoff.
(b) if the destination is below alternate minima then you have to have likewise.
Or have I missed something in your post ?
Vol 3 normally has all the stuff you need to figure the sums although I haven't had an opportunity to run through an NG volume.