Scenario

[Hexyprep]

A week would be fine, I would first turn off the gas/water/electric at the mains to prevent back ups and surges causing issues.
I have enough candles, lanterns (wind up) tourches to last months... but would probably try and use the light and sleep soon after it goes dark. I have a nice big double grill gas BBQ that my naighbours gave me a few weeks back as it was too big for their needs!! ((result)) and enough gas stored to last a couple months if used once a day. It would do for most of my cooking needs. Also a wood burning stove for outdoor use for the rest of it. I have a wind up radio and battery powered ones along with CD players and plenty of story CDs, books and board games to keep us all entertained (if I'm even worrying about that).
I have a water butt for the toilet issue and enough drinking water stored for cooking and drinking for 3 months. I also have a lot of water stored down the side of my shed which can be purified for drinking or used to wash. My nearest stream is a 5 min walk and my nearest river is a 10 min walk. I I also have tablets to purify and a purifying filter bottle which has a lifetime guarantee... so should last a reasonable time anyhow!!
Heat might be an issue... but we all have thermal underwear, jumpers, jackets, hot water bottles and an unreasonable amount of blankets. We actually had 2 weeks with no heat or hot water in the worst of winter a couple years back and it was uncomfortable but we managed.
my one concern would be the food in the freezer as there is much more than a weeks worth. I might be able to smoke some of it on my outdoor woodburner and maybe if its cold enough it would be okay outdoors... but think we might lose some of that.
Not really sure how long we would be okay... but sertainly a week would be fine.