Well thanks for the heads up I've found an auto electrician who said he would solder xt60 for £20 which is what a soldering iron would cost me.
Just out of interest why do soldered ones not catch fire and crimped ones do ?
Two reasons:
Firstly, copper corrodes in air. It doesn't need moisture, just air. It oxidises and the contact resistance goes up, then the contact area will heat up when any current flows. Tin lead solder doesn't oxidise and works as a protective coating of the copper.
Secondly, you need proper equipment to get a proper crimped joint. it's not something you can do with those cheapo crimp tools. the crimp needs to be sufficient to exclude air from the joint, bearing in mind that it's stranded wire and there are gaps between the strands.
DIY crimping is OK for low current connectors, like throttle. LCD, PAS, etc, but not for anything that transmits high current, like batteries or motors.