Considering my mk4 GTI (remapped) did around 30 mpg, my (remapped) mk5 GTI did 28-30 mpg, both my mk6 GTI's did low 30's (remapped), my GTI PP did low to mid 30's it came as no surprise that my R did mid to high 20's.
These are rule of thumb averages from full ownership terms not scientifically computed or anything.
My scientific conclusion tells me that considering all those cars did a similar commute, with a similar diving style progress in making hot hatches more economical has generally been quite good.
I'd put the R's consumption down to the car having a fair sized turbo and an engine mapped for top end performance. Although I rarely used high revs the fact the big turbo needed lots of fuel to produce the BHP figures I'd taken as a foregone conclusion. More power = more fuel burned.
Then there's the weight.
Then there's the other drag inducing axle and propshaft.
If you want a 300PS hatch with 4wd then you accept it's going to cost you a few quid at the super unleaded pump. If you want an automatic version of said car then likely more so.
And then came the Ed40 ClubSport.
I drove 2.5 miles yesterday morning, including several sets of traffic lights and had 30mpg showing on the trip computer when I got to my destination. Cold engine, reasonable ambient air temps, dry roads etc.
I was quite impressed by that so did it again this morning. More or less the same result.
The GTD *could* do that journey at 40mpg (trip computer figures again, which has been fairly accurate in my use) and my PP GTI could just about scrape 32 or 33 yet the R never did that trip in more than 25mpg, 26 at a real push.
Hardly anything academic but I'm using it as a journey that's going to get the worst consumption figures, it mostly uphill with a cold engine start. Lowish revs, lightish throttle inputs but not dawdling.
What does my 2.5 mile acid test prove?
It's the 4wd that saps the fuel consumption (quite possibly).
So that's it then. I've decided that's a fact and as this is the Internet it must be true
In other news, I wish I was as wealthy as the OP so that I could consider £31.5k a bargain for a family hatchback.