Screen time and Passcode issue

I wanted to get rid of my son's screen time restrictions. I signed him out of his iPad and signed myself in then went to sort out screentime. It keeps asking me for a four digit passcode but I can't remember it. I've tried every number I might have used but am stuck. What can I do? I can't remember the screen time passcode or the 6 digit iPad passcode so can't even do a factory reset - help!