If something (in this case a seal or gasket) has a temp spec that is incompatible with conditions one experiences at launch or during flight, then to me that is a design defect that MUST be rectified before approval to fly in ANY conditions.
Oh dear.
IF we followed that policy nothing would ever fly again.
And as for:
Airworthiness Regulation and Air Accident Investigation aren't safe anywhere near the MOD.
One assumes by MOD you mean all of those personnel who work hard on accident investigations, doing their best to find causes and recommend improvements for the future. Bit of a slight for all those who have been involved in numerous perfectly acceptable accident investigations over the years!!