Ok, so I have completed all other factions, given the go for the Omertas and driven out the Khans from the Mojave.
The only thing that remains is making contact with BoS, but when I enter the bunker in Hidden Valley and lockpick the door open, there's just piles of rubble.
Not a damn soul in sight..

What am I supposed to do?

You are in the wrong bunker, there are four possible bunkers you can enter there. Try the one with a tree stump over the door.

Thanks mate!