The station shots for the original movie were made at Carnforth I believe. Dunno about this modern version tho'.
as mentioned, Carnforth station one was the one in the old movie.. i only chime in as i was up there a few weeks back and was impressed, they have a decent part of the station turned into a kind of 'olde-worlde' railway museum, very authentic. The damn big clock featured in the movie is still there. it looks heavy.
Incredibly, in Carnforth station, there is a tiny (about a dozen seats) cinema, or viewing area where you can watch the original Brief Encounter movie whenever you want .. it had a few folks sat watching the movie, it's slightly hidden off the side of the shop, which has a selection of rail / retro type goodies and fudge / fridge magnets / coasters etc, all staffed by (when we were there) some absolutely lovely retired folks who were so wonderful they felt almost like friends, very interesting, lots of rail stories, and were genuinely interested in you and what you were interesed in, which i found humbling and wonderful and quite unusual this day and age.
Highly recommended !