Hello Stuart,
Sorry, as Cliff said, there doesn’t seem to be regular contributors who are into diagnostics to the same extent that you are. Having said that, some knowledgeable diagnostic folks do contribute from time to time when they visit the forum, but I well understand you need answers when you need them.
Although I certainly respect the need for diagnostics, and well appreciate the benefits to be gained from such experience, another viewpoint is one of the old ‘cause and effect’. As I understand it, component x can be shown up as the culprit since it receives its ‘signal ‘ from y, yet the root cause is actually at y - not x.
Of course, this doesn’t help you one bit, but all all I can do is apologise for the lack and response and hope someone might come along shortly.
Meanwhile, kind regards,
Gareth.