Plot hole: The protagonist gets in the exclusive, multi-millionaire, invites-only auction because the invitation is on a printed letter that he faked. This means that the guards at the entrance don't have a guest list to check, and since nobody knows who this person is, the staff does run a background check on his identity when he makes the first outrageous bid...by looking his name up on Wikipedia. That's mighty low standards of security, especially for an auction that was supposed to be for a selected audience and the most important in France.
Plot hole: Burke is murdered so that Doward will be sent out to replace him, as both hold the same rate of CPO sonar operator. But there are many CPO sonar operators in the Royal Navy. How can the GRU be so sure that Doward will be the man chosen to replace him?