Hello @Nigel Horne,
My name is Alejandra and I am happy to assist with your inquiry, and appreciate you contacting LastPass Support!
If you are looking to set up DUO as your athenticathor please follow these steps: https://support.lastpass.com/s/document-item?language=en_US&bundleId=lastpass&topicId=LastPass/t_set_up_and_configure_duo_security_authentication.html&_LANG=enus
Remember that the code neededd to set up can be find insided the DUO admin console.
Kind Regards,
Alejandra
LastPass Tech Support