Now I'm really confused
Just thought I would manually add an appointment - tranferred fine.
So I then opened one of the sectors on the PC and saved it - nothing.
I then opened it, checked the 'all day' box (which was empty - appointment times were there), un-checked it and saved it - transferred fine!
So if I open each appointment, mess with it, put it back as it was and save it it transfers!
There seems to be some sort of 'phantom' selection of the 'all-day appointment' box which my PDA picks up on, but not my phone or my PC