In the Bag o Nails pub they disco dance to KC and The Sunshine Band "Get Down Tonight" and drink shots. 1970 would be too early for disco dancing. the KC and the Sunshine Band song was released in 1975. Drinking shots while common now in the 21st Century would have been very unusual in the UK in 1970.
During the undated second contact with "Alex", the Mossad agent, information about the whereabouts of Ali Hassan Salameh, wanted for the attacks at the Munich Olympics, is presented hidden inside a newspaper dated May 28th, 1971. The Munich massacre took place in September 1972. Since clearly the meeting took place between 1972 and 1973 (after the Olympic Games and before the Yom Kippur war), it makes no sense to use a newspaper from 1971.
Ashraf Marwan left the funeral ceremonies (Gamal Abdel Nasser's) and broke into Gamal's office to search for any important document hoping he'd be able to use them later. Minutes later, Samy Sharaf, suspiciously enters the same office. Before he finds out about Ashraf who's hiding under the president's desk, an officer enter the office and calls Samy Sharaf and asks him to come as Gamal Abdel Nasser wants to see him immediately!!.
It's the year 1970 and Marwan goes into the bar "Bag o' Nails". "Long Cool Woman in a Black Dress" by the Hollies, first released in 1971, is playing. He subsequently dances to "Get Down Tonight" by KC and the Sunshine Band, first released in 1975.
When using a public telephone to call the Israeli embassy, Ashraf Marwan deposits a coin before making his call. UK public telephones of this era did not work in that way. The caller dialed the number & was only required to deposit a coin once the call was connected, not before dialing.
When the Israeli airliner is attacked, the weapons shown are clearly rocket propelled grenades which would be an inappropriate weapon for an attack on an airborne plane. It is likely that the story meant to show the use of stinger missiles.