It was a rather loud bang!

I'm not sure what to say about the starting issue, I don't know anything about how the wasted spark kits work, I suspect it possibly has no spark but I'm not sure what cause that, obviously I'd normally start at the crank sensor/distributor area but in your case thats not entirely applicable. Perhaps a call to MSD may help speed things along to get some info on where to look?

We can try and bang in some new plugs but I'm not overly conviced thats the problem, and I'm totally confused why the hell your car backfired whithout cranking it over, there must have been fuel in the engine, and obviously a spark when you turn on the ignition but I have never seen that before.....