Just to update this thread:
I received the domain yesterday.
When this happened, I immediately started a DRS. That froze the domain and gave me the seller's real name and contact details. His name is Dan Koo or Daniel Koo and he uses a business address at Berkeley Square House, in Mayfair, London.
Someone else (thanks so much!) helped me verify that Dan Koo had been listed as owner of some of the other domains the same seller had listed for sale on DomainLore (prior to GDPR hiding this information). So I knew I had the right guy.
The seller agreed to settle the DRS with a transfer of the domain to me, and Nominet took care of the transfer.
I understand that the seller has completed all domain transfers of the domains he sold on DomainLore, so everyone has been made whole.
It seems the seller signed up on DomainLore with a fake name, anonymous IP address, and a throw-away mobile number that was turned off right away.
Thank you so much to everyone for their help, suggestions, and support! Many people helped me with this and I greatly appreciate it.