"It is curious why NOT would not follow the steeply dipping open end of DE1 towards the south. "

When I spoke with David Graham some weeks back, he indicated that their strategy for E1 was to outline the portion of the deposit that was mineable from the surface (i.e. to a depth of about 250 meters.) Beyond that it becomes much more difficult to target and hit the mineralised zone, and as we have discussed on this forum, surface-mineable deposits are more valuable because of the lower cost in mining them.

I understood this as picking the low-lying fruit. I expect they feel the payback will be faster if they work on other surface anomalies first; I would also expect they will come back to E1 at some point in the future to drill the deeper portion of the deposit.