I am actually using code based on the KitchenSink app, but I managed to get the scrolling working.
For those that may be suffering a similar problem, here's my solution.
I had a tab panel with the following property set...
This didn't allow scrolling, but then when I commented out that line and added the following...
This works for me now. ExtJS 2.0.0pr1 for those that found this using Google (I can't tell you how many times I wished someone would put version numbers on their questions).
pack : 'center',
Thanks anyway Mitchell!