Thanks for the replies,
I have added the breaks after each case
I have also now realized what my problem was, the steppers were operating but only one step at a time due to the run function so it wasn't noticeable.
I'm sorry if my problem was not clear previously I am looking to use the data received by the IR remote (which I understand) to cause the steppers to operate simultaneously for a large number of steps when a signal is received, but I don't know which Accelstepper function to use in order to make this happen instead of the run function.
Once again any pointers would be much appreciated.