You are not alone Richard, several occurrences of chassis cracks in two different sections of chassis and on pre 2014 chassis cars. This thread relates to the most recent one that was detailed in the recall
http://www.talkmorgan.com/ubbthreads.php/topics/520784/1, there are some other threads on this subject as well. There is a FOC repair scheme for this known crack, this should fix the problem. Ensure that you get the inspections for brake pedal and chassis recorded in your service book and that the chassis repair is recorded.
From your post numbers I assume you are not a TM regular and that the recall letter for the brake pedal failure prompted you to get the inspection done? We still await a recall letter for the chassis crack inspection. You would have thought that MMC would have done both recalls on the one letter as they are obviously checking the chassis at the same time as the brake pedal and both issues relate to pre 2014 spec cars.