Hi,
thanks for the replies.
Hopefully I will have time today to do a leakdown test.
And I held the throttle open while cranking.

I checked the valve timing and this is right.

I didn't squirt oil into the bores after doing the comp check.

It doesn't add up to me that the rings are gone as the PSI readings, except for cylinder 1, are all close.

But, if it has been severely overheated then the rings could well be stuffed, but there are no obvious signs that the motor has been cooked.
And it was serviced 4000kms before it broke down.