Well I would never advocate thrashing a new car, but I certainly wouldn't baby it once it is warmed up either. Don't lose too much sleep in slipping into 80% of its potential when the oil is up to 90C.
After 7 VW TDIs, the only one that got babied was low on power, had poor fuel economy and used a litre of oil every 1000 miles or so.
I get my best mpg with Esso, BP and Sainsburys fuel have been fine too. I expected a lot of Shell (old pre-common rail TDIs used to run best on it), but in normal and V-power, the fuel economy and output were noticeably under what Esso gives for me.