<<"We arrive at Zurich on BA 716 at 15.50. Are you aware of the amount of
time we should give ourselves from arrival to boarding the train?">>
Zürich is a fast airport. And, the train station is about a 3 minute walk plus escalator ride after you leave the exit from the arrivals hall ( luggage carousels and customs.)
Factors to consider- probably the most important are-
1.- time to get off the plane, especially if you are in the back- could be 5 minutes or 20 minutes.
2.- transit to pass control and pass control. UK is not a Schengen country, so you will have to go through pass control. Usually fast - 5 to 10 minutes, time to get there...unclear. Depends on where your plane ends up...at the terminal or out at a satellite. Guess at 10 minutes. Could be 20.
3.- Wait for luggage - none if it is carry-on. 5-10 minutes maximum if otherwise, by the time you get to the carousels. Usually..
4.- Time to buy tickest - zero if you have a Swiss Travel Pass; 2 or 3 minutes from a machine if you use a half-fare card, which requires that you buy tickets for each journey.
That adds up to about an hour, and the slowest part is likely to be getting of the plane.
With carry-on and coming from a Schengen country, I have made it to the train platform in 20 minutes, but I was near the front of the plane and it parked very close to the arrivals hall.
With unusually good luck, you cold make the 1640 or 1643 train. Other wise, and definitely possible, the 1740 train, arriving Zermatt at 2114 with one change at Visp. A 6 minute change is no problem there.
If you miss the 1640 or 1643, there is a nice food court on the ground floor of the railroad station. The station is a couple of levels down.
I got those times from the timetable.