Charlotte has just started rolling over (cant roll back yet) and so everytime I put her on her back within 2 mins she is on her front - which is great, except that after a few minutes when she realises she has nothing to do and nowhere to go, she get all worked up and started crying...So she sleeps on her tummy
She has always been a tummy sleeper, and can move her head, but I find I am more confident leaving her on her tummy to sleep if I put her down on her tummy, cos I can position her head and if she is asleep she wont moveto face plant herself...

OMG, so not making sense today! lol Point is, maybe you could try putting her on her tummy to begin with and that way less chance of her rolling herself and faceplanting.