Hi @richardb
Welcome to the Auth0 Community!
Thank you for posting your question. Unfortunately, renaming the MFA factors is not possible.
If you think that a crucial feature, you can submit Product Feedback on our Community page to add more weight and visibility to the request. Here is our link: Feedback - Auth0 Community. You can read our FAQ regarding submitting a feature request here: How do I submit Product feedback or feature requests?
Thanks
Dawid