Fuji Hiro is as close at it gets to actually being in an authentic japanese canteen. You should go here if you want an authentic experience, but not if you're after swanky decor. Also note, the food arrives when it's ready and not in any particular order so it's usually better to share dishes.
What you can expect to find: Reasonably priced noodles, ramen, gyoza etc and a nicely chilled Asahi...with very friendly service.
Image from www.leeds-list.com