Vallis Estate was a mansion owned by Daniel Barton.
In 2020, Daniel Barton organized his birthday party in Vallis Estate. As an appology for interrupting their interview, he invited Yasmin Khan and Ryan Sinclair. They arrived at Vallis Estate accompanied by the Thirteenth Doctor, Graham O'Brien and "O". After being confronted by the Doctor, Barton denied all accusations put to him and angrily left the party in his car. (TV: Spyfall)