I'm quite fond of Zarzar Bazzar in Bristol - not the best food, but its a giant warehouse full of all the cuisines you could think off and you can see the kitchens making it all fresh for you. Depending on if I'm really fancying decent sushi, Sakura in Manchester is pretty good, its a bit different as you order rounds via a tablet and it comes to you, but you do get fined for wasting food.