Yamm at the Mira is has good ingredients (sushi, sashimi, oysters etc) and have dedicated counters for tempura, yakitori, dinner is 500 so lunch should be 3xx..
semi-buffet lunches at most Italian restaurants...
The Sheraton on Nathan Rd. has a restaurant on 17th F. Don't know if they do a lunch up there or how many $$$ go with it but the view of the harbour is great from up there. Happy New Year.