Dave,
Check the wires from the electric starter first as you will find one of them has a fuse in it. It could give you the spark problem as well as the starter motor not working.
1. Check you carby wires are not touching first just pull out one wire and check spark(make sure that it does not touch the body of the mower).
2.I would be checking that the module is not loose as a bad earth will also cause a no spark.
3.If still no spark check that the coil has good earth by removing it and claening where it bolts onto the motor with some sand or emery paper. Then check for spark again
4. If you still have no spark them I would look at replacing the module.
5. If that does not fix it then you have a coil problem.
Hope that this helps. I am still working on the electrical side for the site as it takes a bit of time to do.
Regards,
Bruce