Ok, just to be original I'm gonna pack up lots of food from my house and the local supermarket then go to the shopping centre and barricade the entrances, the good thing about this is that there are very few windows outside and the only way up to the other floors are easily barricaded escalators, except the roof car park but we could defend that quite easily as it makes a nice bottle neck. I'd probably just wait there with others for as long as we could, if the zombies showed no signs of thinning out then I'd probably grab my camping gear and some food and head North and camp out at the lake district or something, assuming that the zombies get that far North and the roads are open. If the roads are closed its a few weeks walk, so I probably wouldn't get far.