In the surrounding area, there are several bars and restaurants to try:
Archduke Bar on Concert Hall Approach between Waterloo Station and the Hall.
Azzuro Restaurant is a short walk away, also between the Hall and Waterloo station
The famous Oxo Tower Restaurant is nearby, where you can have a full meal overlooking the river or just grab a quick drink
For a list of other restaurants in the area, visit www.southbanklondon.com