Audio problem: When Cyril is driving up the bus up the mountainside, and Don is talking to him over his shoulder about Barbara, Cyril is heard to say "Don, Bachelor boy". However this is not what the original line was, as it can be seen that he is speaking different words. The line was probably changed between filiming and recording the over dubs.
Plot hole: When Mr Wrightmore shows up at the gang's hotel room to tell them that Mrs. Winters is having a press conference at 6pm, Don rushes out in order to talk to Barbara and Mr. Wrightmore seems to know what her room number is. But how did he gain that piece of information? Barbara's mum wouldn't have told him the number because she would then know that he would tell the gang, since he is seen standing with them when they arrive in Athens and he says that he's going to get them out of trouble when the police arrest them under Mrs. Winters's orders.