Our early (April) 2012 one cracked at ~7000 miles along with a number of the other ones that were found when cracking first became identified as an issue - this was a good opportunity to have the original cush drive replaced by a Centa with the factory doing the labour of getting the engine out .... the brake pedal recall/fix (for the missing weld) for ours came quite a while later.
My thinking is that the original chassis design is inevitably going to have cracks initiating (inherently because of the design) but the time before they bcome visible (propogation) depends on the quality of welding of a particular chassis and/or the usage....no idea if the bolt in brace is a good solution but the number that cracked even with this brace suggests that cracking had initiated (micro-crack) before the brace was fitted and the brace does not stop crack propogation.
