[NickK-UK]

I have the 1.6 diesel EAT6, but drove the 2.0 GT for over a day.

Firstly - how short.

The 1.6 diesel I don't use it for short commute of the wife, 5-7 minutes is too short by far.

Diesels DO hate short journeys:
* if the engine is allowed to cool between them - the 1.6 does cool rapidly (especially when the engine coolant has not been warmed - see point below about variable cooling).
* the 1.6 take a couple of minutes to get oil properly around it from starting.
* the 1.6 engine design does it's best to get temps up as quickly as possible because the NOx eco figures need the engine to be within the operational temperature range as quick as possible. It varies the cooling to the engine to assist this.
* the DPF needs a good 40mph for at least 20-30 mins to regen, if it doesn't get this it will reattempt regen the next start.. until it gets to the point where the car has to warn the driver before the DPF is blocked to do a long run. Again the engine attempting to regen will increase the temperature of the exhaust gasses and it will impact MPG.
* MPG when warmed up at 70mph over 60+ miles was 55mpg. However when cold and around town you'll be in the 30mpg.. or possibly less. Average 45mpg on mine (EAT6).

We do the odd short run and then weekend jaunts, but the car gets longer 1h+ journeys often.

So 10 miles is probably the minimum, and it will have warmed up and possibly started warming up the rest of the cooling by then. You will still want a long jaunt every so often - if it's a slower road then switch to manual and drop down a gear to increase the revs.