Help - Error running Better Laundry Monitor

I am trying to use the Better Laundry Monitor and having installed the code, and running it, I’m getting an error when the cycle ends. It sends the message out as expected, and seems to be setting CycleOn to false, but I don’t think it’s ending this software loop because it goes on measuring current and sending out the End of Cycle message to my phone periodically (which is really annoying!).

The debug looks like this…

44968931-937d-4825-8ffd-032aad62a0c9 12:34:19 BST: error groovy.lang.MissingPropertyException: No such property: duration for class: script1462787477425954690338
Possible solutions: location @ line 89
44968931-937d-4825-8ffd-032aad62a0c9 12:34:19 BST: debug End of Cycle
44968931-937d-4825-8ffd-032aad62a0c9 12:34:18 BST: trace CycleOn changed to False

I’m not really a programmer, and haven’t done any real coding for decades, but should the variable ‘duration’ be declared somewhere? (because it appears that the error comes when the program tries to execute the line: duration = state.cycleEnd - state.cycleStart

Really appreciate some help debugging this one