Apple told you a £1,000 laptop less than a year old has an acceptable battery life of 4 hrs!?!? That's farcical. Under what circumstances is a customer to accept degradation to 30% of the original capacity is OK?
I use Coconut battery (free app) to monitor mine. My 17" MBP is nearly two years old and still has 96% of it's original capacity.
However, we're a little off-topic here. A dodgy file is not going to cause the BSOD failure.
I have friends who are serial downloaders with no anti-virus software whatsoever and their machines run perfectly.
Another uses Spotify, a dirty piece of software by a dirty company. Her battery life is poor and her machine is terribly slow until she uses it from a different location, then it works just as well as mine because Spotify stream music from your computer to others, so it uses up your bandwidth and battery.
Check your CPU activity with Activity Monitor to see hwat it's up to.
Meanwhile, back at the ranch...
Take the machine in to Apple, quote the various case numbers quoted here and ask for a repair to eliminate the BSOD. THey'll replace all sorts of hardware, delte everything, do a fresh OSX install and it will still fail. You'll have the satisfaction of knowing it's cost them a fortune, then ask for a refund so it costs them even more :-)