>> You have to use terminators (HVD) on the D1000 and A1000.
>> http://sunsolve.sun.com/data/805/805-2624/pdf/
>
> Fitted the correct wide-diff terminators and same result, again after
> deleting the device trees and reboot -- -r
>
> Juggling the disks now see if that helps narrow things down...

Think I solved it. After a lot of trial and error seems two identical
HP-badged Seagate drives don't wanna play ball.

Digging out some replacements now...

Steve