I have no special knowledge of the Green Party leadership challenge. I am not a member of the party, and I have no useful sources. More importantly, I think its a matter for party members, rather than random bloggers, to resolve. But the general consensus is that there's nothing really to it, and that Green members are a little annoyed at having it raised (oh, and apparently having a democratic party which permits the leadership to be challenged is "crazy" - another sign of the anti-democratic strain in our political journalists).
And then there's Rachel Smalley:
[L]et me tell you something - in politics, there is never smoke without fire. [Hay] wouldn't have done this if he didn't have the numbers. I think the Greens are frustrated at the moment, possibly a bit anxious, and this is why...
The big problem with this? It assumes that those involved are uber-rational Machiavellians. And the conclusion is entirely an artefact of that assumption.
Real politicians are not spherical entities moving in a perfect vaccuum (or that other simplifying assumption, the "perfectly-informed rational market actor"). They are frequently egotistical, lack perfect information, and are not solely driven by the acquisition of power. We've seen plenty of examples in recent years of politicians who can't count, and who have launched leadership challenges without having the numbers - the present Leader of the Opposition among them. Absent compelling evidence to the contrary, this looks like more of the same.