Taro

• TIPS: Bills come with 10% service charge added. None of this goes to the waiters/waitresses, though best to confirm with the manager rather than the staff (some of them are new; others don't speak very good English).
  
• DO: Eat here. The food is great. Order the salted mackrel; drink the plum wine; get a table away for the window (it can get drafty).
  
• DON'T: Pay the service charge. Though the manager doesn't seem to understand the word "discretionary", you can ask for it to be removed from your bill and then leave a tip of the waiter/waitress.
  
• Two other issues to bear in mind: you get served by several different staff, so it's hard to know who you should give your cash tip to at the end; it's a family-run business, so the money probably ends up in the same family pot anyway!
  

Nobu

• Tips split between army of waiters (you're never served by just one person), maitre d', kitchen staff, bar staff: basically everyone except management. Waitresses reluctant to confirm this, but manager will*.
• DO: Go with someone who's picking up the tab (it ain't cheap), order the bento box and the papaya & carrot juice - it's £6.50, but it's yum!
• DON'T: Pay the discretionary service charge of 15% on your card; better to leave a cash tip. The more senior the waiter, the more of a share of the tip he/she gets.

*there are philosophical arguments as to whether your "tip" should go to kitchen staff, bartenders and the like. Why should the waiter be the only one to receive a gratuity? If so, pay the service charge at Nobu with a clear conscience. If not, then you may have to go somewhere else.