Thanks for your suggestion, and I just put a note about this in the original post. I'd be interested to see the command for running block erupters under linux for the most recent version 3.3.1. Adafruit did say there was a problem with this under Raspbian, but that might just be because they were trying to use -S tags.
Great, thanks. I only mentioned it just in case someone downloaded the latest cgminer instead (like not everybody reads the instructions in full before starting

).
I had a scan through the cgminer support forum, and it looks like its best to stick with 3.1.1 for now vis
https://bitcointalk.org/index.php?topic=28402.msg2632152#msg2632152 (lead developer recommends 3.1.1 as newer versions are unstable on RPi).