Having the first class at the London end of the longer Meridians can cause delays northbound at Chesterfield the way the stop boards are arranged the last coach is about level with the station entrance, bad enough if standard is at the rear, but when pax have to walk 3 coaches down the platform after the train has stopped it does add on a minute of so to the dwell time.
Neither the PIS nor the automated announcements seem to be able to cope with double Voyagers, they can't say things like 'First class is at the front and in the middle of the train'