To be honest Paul I've just had enough.
As you said at the outset an engine that has just run perfectly with temp exactly mid way, sounding great, not smoking or using oil and with all the correct fluids on board doesn't seize up the next day on a driveway when it's cold.
Nor do I understand why even if it did suffer this seemingly impossible huge mechanical failure it would at the exact same time kill completely
(to the extent that I wasn't getting any dash lights) a brand new 4 day old battery.
.
.
.
having done precisely the same to the preceeding battery about 6 days before.
Where's the connection there?
In my view conclusion of diagnosis after driving it, cleaning it, modifying it, personalising it and basically loving it for over 13yrs and 140,000 miles is extremely important.
I have spent a lot on it recently
(including a H/G replacement) but only after much careful thought and wouldn't have done so if I had any inkling of another issue.
Luke recently posted here in another thread how after the new H/G it had compression of 185 across all cylinders.
.
.
not a sign of a failing motor.
I want to know what has killed it.
Concluding it has just expired on my drive is like concluding JFK died of natural causes.