- Click on your text box, then custom animation in the task pane on the right hand side
- Click Add...
- Select Appear
- Right click the animation that appears in the box and select Effect Options...
- On the Text Animation tab, choose 'Group Text: By 1st level paragraphs'
So intuitive! I couldn't get it to apply to all slides by doing this to the master so I just did it to one slide then used 'Duplicate Slide'.
Well done to both Powerpoint and OO for making it easy to do all sorts of distracting and stupid flying animations but hiding useful features under a maze of configuration.