Is there any way to find out when a timer script will next run (or if in fact, whether one is currently scheduled)?
Only if you take steps to set up something that you can check. The script performed by the Install OnTImer Script step could, for example, put the time of the next time it will be run into a global variable--as could the script that initializes the timer in the first place.
Then you can check that global variable for a value. If it's empty, there's no timer set. If it has a value, the value can be the time it will next trigger the OnTImer controlled script.
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