Thanks for the suggestions, sadly the result is the same, clearly something in the client is preventing it from being submitted (I can create any other new character fine):

- Use Y'shtola Rhul as name - no name taken error, only the same cancel prompt
- Selecting a different class - same cancel prompt
- Pressing enter key after selecting a name - doesn't do anything for me
- Gamepad - same cancel prompt (funny I get the same cancel prompt from pressing both A and B on the xbox controller)

Another video showing the above:
https://youtu.be/Bn7XJyHDXx8