Intel/Lenovo SED/OPAL SSD Management

[lanovo]

I'm looking at this SSD (Intel 7600p Pro, Part Number SSDPEKKFxxxG8L) that appears to be supplied with various ThinkPad models.
I've been trying to enable authorisation for hardware encryption. Unfortunately I am not having much success, the sed program fails to take ownership of the drive. I also tried the ThinkPad Drive Erase DOS/EFI utility to reset the crypto key (aka PSID revert) and it's still a no go.

The drive itself is otherwise useable and performs really well. I've tried it on a couple of 7600p Pro drives and the results are the same on all drives. The firmware on the drives is updated to the latest L15P. Looking for any ideas to get it working... ?