Seeing u live in a cool/cold climate and u mention the battery charge light flickering, i'de be looking at the battery as the problem before u replace all the ignition parts. Put a multimeter across the batt terms (ign off) and check volts at least 12volt. If any lower I don't think u have a charged battery and maybe not enough volts to trigger the electronic ignition. Also, check the wiring connector to the rectifier
under the seat. I accidentally dislodged it and at idle the charge light stayed on and only went out at high revs. It turned out the wiring connector needed to be pressed home and all was ok. That connector is not real tight on my bike, so I slightly bent the tabs to give it a firmer fit.
Also use the choke to start up. If its cold weather, pull it out half way to full when starting.
Check the oil level isn't too high in the sight glass. You can't check oil level with bike on the side stand, you have to pull it up dead vertical. A lot of riders seem to have overfilled the engine. It only takes a bit over 1 litre. Other bike manufacturers of this engine capacity must have bigger sumps and riders are just tipping more oil in the Zong than it needs.
Check your spark plug and gap. It is type D8EA or DR8EA gapped to 0.6-0.7mm. The gap on mine is critical for smooth idle.
I just googled "Zong uk parts" for spares and the first one that comes up is : http://www.china-parts.co.uk/
...They seem to have all the parts in their online catalogue including cdi /coil etc. Have u tried them?