last few years I've been paranoid about my fuel consumption being too high?

[hemeldude]

And I believe this started well in my head when I decided to help jump start someone very old looking European car, God knows what make it was, maybe like the one from terminator 2, anyway I was helpful, anyway since then or possibly after the emissions scandel they did the fix who knows I felt my car was burning too much petrol, I was even using Shell/BP to refuel!
Even after a few services it didn't improve, even had the mechanic find some grinding with the rear break and he fixed it still same issue, now I'm sure it was burning to much i'd look at the fuel gauge and after a 20 minute drive to my G/F's house I could see it moved we're talking like 12 miles. I remember i used to make so many damn journeys to her house in the month and not have to refuel for ages, okay this isn't that much of a scienfic approach but I decided to see how much mielage I can do with a quarter of a tank and it's probably around 130 miles, tons of short 2.5 mile jounryes and 3 or 4 longish journeys on the motorway, anyway the mpg showed as 69.9mpg at say 70mph or less, anyway I'm pretty sure it was stuck at 49mpg at this same speed last few years hence the paranoia, the only thing I have changed this time is use Sainsburys petrol???
A3 Sline 2011 black edition diseal, manual, 147bhp, 2 door 2.0 TDI EA61 XTY plate, any ideas ? Approaching 90k mileage literally 50 miles to go or so.

 

[prt57]

Easy way to check that the brakes are not binding is to stop on the slightest incline taking care no other cars are behind you and the car should start to move backwards unless your foot is on the brakes.
Has the car been serviced including replacement of the air filter?
Driving style will affect consumption plus short journeys will lower the mpg massively.

 

[NHN]

49mpg is respectable tbh, not far of reality imho, short journeys aren't helpful tbh on mpg.

 

[abmat]

Supermarkets also sell fuel that is getting to the end of its life. Plus all the additives they add in so it’s good enough to sell. A few years ago it was destroying land rover engines.

Sainsburys fuel is *****. There’s a reason it’s cheap. Fuel isn’t as good a quality as it used to be as it has more stuff added to make it cleaner and improve the retailers margins.