When my fondant cracks, it’s usually because it’s too dry. I knead in some shortening and sometimes a bit of glycerin too. This maybe helpful too:
http://www.cakecentral.com/blog/61810/the-fundamentals-of-gunging

-- Creativity is God's gift to us. Using our creativity is our gift back to God. Clarky's Cakes 😎

Rub shortening over the cracks, rub it in gently. Let it sit overnight and they will disappear. It is because the fondant is dry and overworked. When I colour fondant I do it the day before I use it. Then it can sit overnight or longer before I start working with it again.

-- Teri, Ontario, Canada http://www.TeriLovesCake.ca

It may also be underworked & not have enough elasticity -you need to knead all the colours separately before putting them together so that once together you don’t have too much kneading to do, which would mean losing the pattern.

-- Cakes By Samantha

Thanks guys! Maybe I’m not working the fondant enough?? Will try a bit of trek next time around

-- Sarah x