Loss of power?

Well I noticed it a couple of days ago on my new A3 1.4 TFSI which I have had for just under a month..

I put some fuel in from my local BP station and drove it back home and everything seemed fine? Then the next day I got in it and it seemed to be sluggish, and didn't seem to go as well as it did, without the punch when the turbo kicks in? I thought it must be one of those slow days haha.. and decided to rev it abit and hopefully tomorrow it might be back to normal, but it isn't! Today it was the same, slight delay on starting up and just seems to be lazy! So I took it to a Total petrol station to give it some of that performance petrol and it seems to be running slightly better.. but its mixed with the BP fuel!

Any ideas? Does this sound fuel related, or is it normal as the car hasn't done 1000 miles yet!

Thanks for your replies. I usually just stick to the normal BP one, but after what has happened to mine I have lost all faith in it! I will give the higher octane ago next time im due a refill, but I will be running the tank down first! I've taken it to 5 1/2 a few times today, had the legs on a 2.0TDI GT Golf (140?) so it seems to have become abit better, but thats only since putting in the better fuel at total. The car has done 930 miles now!