That really was a scary moment - glad you came through.
I seem to remember a thread about chrome chain guards breaking on the old forum - the debate was that it could be either the front bolt coming loose/not being torqued corectly when guard replaced and allowing the chainguard to vibrate and hence fatigue the bracket - or the actual chrome plating itself having a metalurgical effect on the steel causing the bracket part to be weaker.
After reading that thread I decided to just paint mine instead of getting the chrome guard. May be worth looking up the old thread
