Tom Burns and the Duke of Windsor's case

Jimmy Burns wrote the biography of his father, Tom Burns, press attaché to the British Embassy in Madrid under the orders of Sir Samuel Hoare [in his biography, Ambassador with a Special Mission, Hoare however makes no mention to Burns]. The book recall two episodes occurred in Portugal during that period, the case of the Duke of Windsor travel to Lisbon and Leslie Howard’s tragic flight from Portugal back home.
Windsor’s case is the story of a German plot to «kidnap» him, or at least to convince former Edward VIII to move from Ricardo Espírito Santos's villa in Cascais to the North of Portugal and from there to Castelo Rodrigo, where a joint German-Spanish operation would later transfer him to Berlin. In the capital of the Reich the former King could proclaim his return to the British Throne, from which he had abdicate in order to keep his marriage with Ms. Salis Simpson, an American divorcee that had conquered his heart.
Burns recalls how, acting with the agreement of the Foreign Office, the Windsor’s were entertained in Madrid and at the same time discreetly monitored for their contacts with Franco’s entourage, not knowing that the Germans were acting behind the scenes in order to keep them in Spain.
Later, after the Royal Couple moved to Lisbon, after 2nd July 1940, Burns traveled to Lisbon by train, where his second Marcus Cheke was working in the British Embassy, with close ties to David Eccles. He met the Duke but, despite the fact he mentioned his staying in this country in a letter he wrote to Ann Bowes-Lyon, little is known about the nature of his mission. Neither in his memoirs can be found any hint about what Burns is really up to in Lisbon.
Remarking that this rendezvous anticipated Walter Turner Monckton, former lawyer of the Duke, journey to Lisbon where he manage to convince HRH to accept the nomination as Governor of Bahamas – in a first move Churchill admitted to make him face martial court for leaving France without permission – the author of Papa Spy speculates: «another possibility is that Burns had taken the initiative to seek out the Duke, as part of a covert diplomatic operation which was stamped with Churchill’s personal authority».
An ambiguous case continues without any sound reply: why was Tom Burns doing in Lisbon and why he met the Duke in the Casino Estoril? Another topic gets no answer: one of the key contacts Walter Schellenberg [Section VI of Reich Sicherheit Amt] used in Lisbon – where he came in order to coordinate “Operation Willi”, the German «kidnap» plan, was in the Portuguese secret police [PVDE] «a double agent working for the British». Jimmy does not reveal the name. As we pointed in one article published about this case, untrusting Agostinho Lourenço [PVDE chief], Schellenberg had made arrangements with José Catela [secretary-general of the police] that he quotes ironically as «C» in his messages to Berlin. Is Catela the German V-Mann and a British double agent?