It appears the 'quality of design' charge wasn't dropped, per se, but HSE conceded (for some extraordinary reason) that CAD wasn't available to Martin-Baker in 1947. Better to say HSE agreed the level of severity was lower than at first implied.
This doesn't detract from the fact that the offending design, and the resultant risk of the Scissor Shackle/Drogue Shackle jamming due to nut over-tightening, was designed out in 1990, but MoD declined to adopt the modification in Hawk. The 1 in 115 years calculation was not adjusted when poor training and engineering practices developed. In any case, the existence of a minor mod that eliminated the risk altogether, meant MoD bore a risk in Hawk that was not ALARP.
I understand the judge expressed uncertainty as to what to do. Hence, the 10 days to think. She was less than pleased at M-B's last minute change of plea. A few days previously, having been informed of evidence concealed by MoD, she had the sense to call it forward. But she didn't ask why HSE had proceeded in the face of this evidence, which raised considerable doubt over the safety of the prosecution. Perhaps she's just got to accept they pleaded.
It will be interesting to see what she does. I keep thinking of this...
1. 56 of the SI's 60 recommendations were mandated policy.
2. All 17 contributory factors were MoD liabilities.
3. Of the 3 aggravating factors, 2 were MoD liabilities, and one shared with M-B.
4. Of the 6 other factors, 5 were MoD liabilities, and one shared with M-B.
5. All 13 observations were MoD liabilities.