I said time. The 745s aren't commuter trains, they're perfectly fine for a journey like London to Norwich, which in a different universe could have been a NSE route like Waterloo to Weymouth or Exeter.
Sorry, I didn't mean it to read as disagreeing your post. I've always felt that a train that once was an 'IC' service is not the same as we have now where the service covers similar towns and cities. The biggest difference is the time the train takes to make the journey. So a Norwich to London service takes around 100 minutes for a 115 mile journey. That's about the same time it takes to get a fast train from Portsmouth Harbour to Waterloo, - just 74 miles. Also similar for London to Cardiff, just under 2 hours for 144 miles*.
In each of those journeys, the passenger sits in a seat travelling along at whatever speed the route allows, - the fact that some journeys cover more distance in the same time is irrelevant to a person sitting down. Equally irrelevant is the fact that before WW2, the journey might have taken nearly twice as long justifying different seats, - the deal was to get passengers there.
* The 125mph routes require faster trains, which may need different suspension etc.., but that doesn't affect the seat design, lighting colour or decor, (some here argue that the seats on the 80Xs aren't any better than those on trains deployes for much shorter journeys)!