I have a version D TR-31 keyblock (which contains an AES Key for use in CMAC), and have the ZCMK key used, what is the method which I can use to extract the key from the TR-31 keyblock? I'll do my own development.
This is specified in the TR-31 specification, namely ASC X9 TR 31-2018, Interoperable Secure Key Exchange Key Block Specification.
It is copyrighted so I cannot provide a better answer.
You can buy the document at the ANSI web store.