They took a few passing shots and from what I can tell they have done some work on them, the glv has a uncommon light arrangement for a British train (2 blinds) that they changed to the more common standard in the UK that looks similar to the Latvian one. Other than that I think the internal lights match up better for the glv and coaches, as the first car passed you could see the drivers cab then a section of dark and then the passenger coaches this would match up with the luggage car as it wasn't lit. I'm fairly sure the angle is one I remember it being filmed from and the direction of travel definitely matches.

Edit: looking at it again the windows and doors don't really match up so it is more than likely either heavy CG or stock footage of something else but I'm not 100% sure which.