Hi Nev,
I'm guessing, but from where the wire comes out through the crankcase it will be points/condenser ignition so the lack of spark can be any of those or the coil. Not sure but you may be able to fit an electronic coil from any of the thousands of Briggs rotary mower motors. If you can give me the coil mounting bolt centers and a measurement from center of one of the coil mounting bolts to the flywheel I can check to see if the later coils will fit, pretty sure it should, if so then you will have spark.
