On page 278 of the PDF it states:
Audio Meters panel
1. Select Window > Audio Meters.
2. Right-click the panel and use the options to do the following…
In the PDF, a nice little graphic of Audio Meters is shown underneath (1) (see below).
When I go to the Window menu, however, Audio Meters is permanently ticked. Nothing I do can untick it. I can open the Audio Mixer. I understand how that works – looks similar to the Tascam Portastudio 144 I've had since the early 80s – but when I try Audio Meters… nothing.
Reset or change workspaces.
Must have been hidden somewhere, but resetting the workspaces brought it back.