Not able to comment on safety issues at the application stage? I can only presume that the MoD take that particular tack on grounds of cost. I am a safety engineer by profession, and looking at conceptual designs at an early stage is a major part of my job. By the time you have got a firm design, it will cost a great deal of money to change it. Far better and cheaper to look at things at the "fag packet" stage...major issues may already be apparent and will cost peanuts to put right.
On reflection, the MoD wouldn't worry too much about that aspect...the money to put a flawed design right wouldn't come out of their pockets, would it?