Glad your ok Pete and in good spirits too!
From my view point it was a pretty awful launch, should have used a bit more of the grass behind you to start with and yes you should have aborted takeoff, but thats all with the benefit of hindsight, some of my takeoffs where I've nearly hit fences could have gone same way but I got lucky!
I think your fireball was just a freak incident but nevertheless it shows that it CAN happen and made me think a lot more about going flying on my own, imagine that!
As a result I've now ordered a load of burns treatment for my first aid kit, a new fire extinguisher (one that works when you press the handle) and am looking for a tiny one that you can fly with!
So, hopefully there will be a positive outcome from your accident matey, it always takes an incident like that to improve safety, and I'm glad there's guinea pigs out there like you pete!!
Here's to a speedy recovery!
Malc