The 100,000 figure is for the Greens alone. Other members of the coalition have also collected tens of thousands of signatures. The speed at which signatures are being collected makes an accurate combined total difficult, but it is approaching 200,000 and the coalition as a whole is collecting around 2,000 signatures a day.Which, if you think about it, means the Greens are doing half the work (rather more if you look at weekly figures, where the Greens are getting 10,000 signatures a week). Labour people may want to think about what that means for their party, and what they can do to motivate and organise their remaining activists.
(Meanwhile, I'll be out collecting signatures again this weekend. I've done over 500 so far, and have upped my personal target to a thousand)