Unfurling Bertinet croissants

Need some help.

Did a batch of croissants a la Bertinet recipe from "Crust", and although they came out reasonably nice looking....

.... some of them (like the one in the middle of the picture) "unravelled" as they baked.  They still tasted good, but I'm trying to improve the aesthetic.

I'm guessing that placing them point down on the baking sheet would help (although none of the properly-shaped ones were done that way), but any hints to keep this from happening much appreciated.

Thanks in advance!