Finally logging onto the computer; there were all the posts lined up in the queue as drafts waiting to be posted.
A small amount of Googling revealed the true problem. Personal incompetence. I had been touching the wrong button on the phone. Instead of pressing the arrow for 'publish' (I thought that was going to take me to another screen!) I was pressing the little disk button which I thought would save and publish. As it happens, only save.
Now I know.
Usual service will resume from here onwards!