I can't comment on the accuracy of the alleged failings by contractors, but I do know that many similar cases in the past have resulted in MoD taking no action and swallowing the cost, even after fatal accidents. The contractor has a ready-made defence if it can demonstrate any laxity in MoD's application of their own regulations. The obvious first question is - is there a stable and maintained build standard against which the work is to be conducted? As Chug has alluded to, the chances of this are somewhere south of zero. Ergo, there will be no valid safety case. This is all very familiar.