Here's the place: Tai Wu Cantonese Restaurant

Click on the buffet link and marvel; it's worth going for the Crispy Aromatic Duck alone which appears in a magic tray which never runs out (or a new comes along in a second).

It's not far from The Palace and two minutes from The Bridgewater Hall. There's the usual restaurant at ground level but go through the double doors to the right and down the stairs and you're in.