Found the fix here, which disables fiq_split – to allow this USB1.1 device to work correctly.
Next challenge is to get the Logitech QuickCam Pro 4000 – which seems to timeout when accessed – possibly a power supply issue:
pi@raspberrypi ~ $ sudo fswebcam -d /dev/video0 -r 160x120 test3.jpeg --- Opening /dev/video0... Trying source module v4l2... /dev/video0 opened. No input was specified, using the first. --- Capturing frame... Timed out waiting for frame! No frames captured.