It can also happen Giles, that they will go dormant at some point and to spare of the anxiety I went through, I'll post a picture with the dormant seedlings. I have no patience or space to keep empty pots so I always check on this sort of things. Amazing how strong the root system is, so I potted them in very early spring in individual pots.
If someone wants to speed up the process though, a GA3 treatment - 1000 ppm will result in germination with the true leaf, just like for Podophyllum hexandrum (and no negative effects on the seedlings).