No, I didn't try to update the contact email that hasn't changed since 2006 when LP transferred the domain to my account and worked just fine when I requested the password reset.
Checking emails, I got multiple renewal notifications in 2008, 2010, 2012.
For 2014 I manually renewed it in June when I was doing another domain.
For 2016 it was auto-renewed. (I don't remember if I asked for that or not.)
2018 was probably auto-renewed, but the email doesn't clarify.
I'm guessing it tried to auto-renew this year, but that failed (since they had an old card saved), and rather than actually notify me about it they decided to tell the person who had it 14 years ago instead.
Had planned to move away from 123-reg after they tried charging every UK domain owner an additional £6 a year per domain for "ownership protection", but I'd forgotten about that. I'll wait a few weeks to make sure the renewal goes through fully and then transfer it to my enom account instead.
EDITED: 23 Sep 2020 14:36 by BOUGHTONP