Many thanks for the replies so far guys - very helpful.
To answer the question from 'Watts' and be a little more specific - my short journeys would be around 5 miles in length and a mix of fairly heavy stop start traffic and fastish flowing B roads.
Cheers
My 245 DSG just hit 3k since it arrived at start of June. My daily commute is about 6 miles each way in a lots of stop start traffic and hills. Most days I struggle to get much over 25mpg on way in and around 20 on way home... (its more uphill and stationary traffic when I leave work).
Did around a 200 mile trip last week, lot of which was on the M1 and averaged 40 for the whole trip - sat around 75-80 on the motorway parts.
It completely depends on the roads, the traffic and how you apply your right foot. If you are stop start in traffic you aren't going to be hitting over 30 mpg. As has been said before, if you are really concerned about mpg, best opting for the GTD.