I am not sure what the recommended minimum age for tummy sleeping is, but I figured as Iwent in there after every time she had a sleep and she would be on her tummy anyway I thought it was time to just put her down like that. Her sleeping has been so much better since we started that, she is still waking for her 2 am bottle which she gulps down ( I am still dubious as to whether she wants it due to hunger or comfort) but it is working at the moment so I am not going to change it, as she takes it and then settles straight back into sleep. This morning she slept untill 6:15 which is a huge improvement!