Cycleosis

 Because it isn't on they waymarked trails. The first trail and the steps can be found off the fire road at the bottom of the path down from the bird of prey car park.

The second one is above this and actually takes you off the "play trail" (footpath) down towards the first one in the video. It's really hard to find and in the winter fairly close to unrideable. The third one is part of the XC course which is only marked out for races. I'll try and post a map at some stage.

 whereabouts is this, because it's nowhere near the marked trails and i could never find it before:S