Thanks for getting back to me.
Did the same thing on my colleagues PC using Firefox and on my home PC using IE7 and XP.
It's really weird as no matter where you drop it, it moves it down by an hour. So if event 6 was at 12pm and we move it one day to the right, it highlights 12pm as the start date Ok, but then when you drop it drops it at 1pm.
Ace package and keen to use it for a client so hope it's something trivial.