Home assistant username lost

I set up a pi with HAOS some months back and its sat data logging temperatures for me since.

Had to power it off the other day and on powering it back on when I log onto homeassistant on web browser it asks for user name and password.

I know what my regular passwords are, but can not for the life of me remember setting up a username for it.

Is there any work around for this without the aid of a computer running linux OS? I plugged monitor and keyboard into the PI to get in that way but still requires login details. Am I looking at wiping the SD card and setting up again from scratch?

Thanks
J