I was re-listening to an old episode of RHLSTP from last year when Peter Serafinowicz is talking about his experience working on TPM. Very funny stuff, if you haven't yet listened check it out (Free of charge)...
RHLSTP Episode 12: Peter Serafinowic
About 25 or so minutes of Star Wars chat from around 12.00 to 38.00. Lots of insider info amongst the laughs.
"Fans of Star Wars will be creaming out of their arm pits when they hear his tales of working with George Lucas and having to pay to go to the premiere. Astonishing stuff. Rich provides an alternate reading of Darth Maul for the next director's cut"