Thanks, I'll give this a whirl, I've just levelled up to 5th lvl in the Catacombs.
Just to confirm this works.
In summary it appears that following conditions are required to activate White March Part 1;
# Have become Warden of Caed Nua
# Have started Act 2 by travelling to Defiance Bay
# Have attended Leaden Key meeting in Temple of Woedica in Defiance Bay
As a footnote be well prepared when you first travel to White March!