In the 1980’s there were three JFK departures from LHR 175/177/179. I don’t remember any of them having any particular cache re their departure times.

The 175 was turned round become the 174 to LHR. The 177 (occasionally operated by a TriStar) became the 176. The 179 overnighted at JFK to become the 178 “daylight maniac” as it was known by the crew. The 178 was also unique in that it always provided that’s morning’s London papers, as they were brought in on the first Concorde service.

The 117 was the first additional service launched in the early 90’s departing LHR early morning around 8.30ish and was operated by a 767. The aircraft then sat on the ground at JFK and operated the 116 back to LHR departing around 22.30/23.00. It was also unique in that initially service was a cold snack ex JFK and a hot breakfast into London. This was short lived and changed to the traditional hot meal and continental breakfast in to LHR. Why 117 was selected I don’t know, but I suspect that’s where the 112/3/4/5 range came from.

As already posted, the 182/3 was the ex MAN JFK flight numbers, and 172/3 the ex LGW JFK numbers. For a short while in the late 20’s BA also operated a 180/1 service. This was using an AA slot while AA were completing the refit mods on their 777 fleet.