Looking for a diesel automatic that I can sleep in if I have to.

I travel a lot abroad for work and a number of times have been stuck or reached somewhere too late to get a hotel, so I need a vehicle that can do regular commuting (outer london), also several long trips abroad each year for work that would not be too bad to sleep the odd night in discreetly if I get stuck.

Would consider a small motability-type vehicle as this might give a roomier feel if stuck in the car, however most seem too short to accommodate or temporarily convert seats etc.

Vehicle must be reliable. Would consider petrol if you feel mileage benefit with this type of mileage really does not make a difference however when abroad I usually make sure to refuel with far cheaper diesel and so far diesel vehicles have cost me less overall.