Rather sadly I maintain a spreadsheet of my fuel economy for my ED 30 - I also kept figures for the previous Mk5 GTI I owned.
In the ED 30 over the last 6848.2 miles I've averaged 29.5 mpg.
In the previous GTI I averaged 29.1 mpg over 27322.7 miles.
All measurements were taken using full tank loads and only ever Shell V Power fuel. I commute about 80 miles a day - a mixture of dual carriageway, A roads, B roads and a bit of town roads.
The spreadsheet also calcs cost per mile (in petrol) and there are a couple of graphs. The graphs are quite interesting - they clearly show as a trend how fuel economy has improved as the car has gained more and more miles.
The range of mpg's per tank achieved is quite interesting - worst was 24.4

best was 38.6.
Anyway, anorak off now

Hopefully, spreadsheet can be viewed here.....
http://spreadsheets.google.com/pub?key=pziXJrPF01oKyub_dqUuwMAGraphs reproduced below...

