Ok,
I think I've found out what I was doing wrong, not sure why I got the behavior I did but here's the code that works first time but not thereafter :-
mySprite = CreateSprite(LoadImage("bunny.png"))
tweenSprite = CreateTweenSprite(1)
SetTweenSpriteX(mySprite, 0, 100-GetSpriteWidth(mySprite), TweenEaseIn1())
PlayTweenSprite(tweenSprite, mySprite, 0)
Do
UpdateAllTweens(GetFrameTime())
Sync()
Loop
I scanned the code and noticed I had a mistake here :-
SetTweenSpriteX(mySprite, 0, 100-GetSpriteWidth(mySprite), TweenEaseIn1())
...should be...
SetTweenSpriteX(tweenSprite, 0, 100-GetSpriteWidth(mySprite), TweenEaseIn1())
I didn't see it because it was working and assumed a bug doh, although it looks like there's a bug been found, sorry for wasting your time a bit guys
Bit of learning curve still for me! I'd still like to know why it worked first time, will have a little dig and debug as there's something to be learned!
Pete