Ive just traded my 2007 Ibiza 1.9tdi in for a 2006 Golf GTI, and although i was expecting nowhere near the 50+ mpg i was seeing on the diesel i was still expecting a lot better than I'm getting on the GTI. On short trips around town I'm not seeing anything above 20mpg usually around 12-15 and on a 2 hour motorway journey taking it easy, always below 80 I've yet to see it above 32mpg. Is this normal? Ive read some people getting 40mpg on motorway runs?? Love the car, so much nicer to drive than the Ibiza but i just can't afford to be putting that much petrol in, the ibiza cupra tdi is calling my name 
I think there's some mildly mis-sold or mis-purchased expectation in here unfortunately fella. You won't 'often get 40mpg on motorway runs' in a k03 or k04 GTI, that's just unrealistic. Even the most finely serviced, looked after, oil and tyre pressure maintained GTI won't do that seamlessly, even cruising below peak speeds.
The highest I ever got from mine was 44MPG over a run, but bear in mind that was a 300 mile round trip and I had to drive with economy in mind to come anywhere close.
On the way to work (a 12 mile commute one way, mixture of A and B roads 30-60mph limits) I would see 33 or 34mpg most days, but that's also taking it very steady. It would also include cruising velocity of 60-62mph for the stretch of dual carriageway (4 miles or so). It's intently boring but that's realistically the only way you'll get close to any quoted economy figures as well as close to the manufacturer quoted figures.
Blast around town and you'll see low 20mpg's, without doubt. Also, if I did the same commute I just mentioned using boost (a typical late morning
) while traveling up towards three figure motorway speeds on the A14, I could expect no better than a 25mpg figure simply because when using the performance, that's the volume of fuel used to deliver it.
In 3.5 years of owning my 2006 k03 GTI I saw 40mpg less than a handful of times (even on long journeys) and that was really trying.
Don't be under any false illusions, it's not built and designed for steady MPG figures
What you are getting seems about right of most of the driving cost experiences on here.
