Hello Frieder,
I don’t think I explained myself properly. One of the tracks played the audio ok ( e.g drum track) The other 3 or so tracks had the edit cubes in position but no audio in them. It’s suggests that some of the audio transferred ok, but not all. I’m not sure if this is coincidence but the track that played ok was the first ‘save’ I made. The audio that didn’t transfer were the edits I did a couple of days later, then saved again.
I agree there seems to be some corruption in the file. As this is the first one I have made it makes me not to even want to bother making another one. I spent some time making it and there’s nothing to suggest it won’t happen again if I start another track. I’ve even turned back to nano studio in desperation 
I just want to make some beats on my iPad.
I’ll send you the files I saved via iTunes, what’s your email address?
Many thanks