commuter travel is pack'em in high density whereas long distance is lower density, room for luggage, decent catering.So that would be your description of a Voyager or Pendolino would it? Must be a different sort from the ones I have travelled on, with airline seats aplenty and even less window glass than a Mk3 - trains which have been pilloried in many another thread here. And a Chiltern Clubman isn't exactly long-distance express stock either, better than a Turbo that hasn't been touched in 16 years, but still an underfloor engine
DMU▸ , with 1/3, 2/3 doors.
At the time of day in question, I should think the numbers driving elsewhere are insignificant - Chiltern's fare advantage is nothing like as clear-cut off-peak and most people aren't travelling for work, so approach their journeys rather differently. If you travelled from Bicester North, you would find parking spaces very hard to find off-peak, while at Banbury, you will have a long walk from whichever of the industrial units in use as overspill parking still has spaces free by that time.
I never said that those of you who appear to prefer to drive elsewhere, then catch a train and have an overall journey time just the same or longer than using the Cotswold Line, were a figment of anyone's imagination - but there are many business people in Worcester who do still use the route.
But several people here constantly assert the numbers going elsewhere are not insignificant, so how about one of you enlightening us with your best guess?