I know this thread is ancient, but the interesting thing about the head removed on Bonzos kit during recording has been discussed and debated for years. Jimmy brought it up very recently in an interview discussing the recording of "In Through the Out Door" at Polar studios. To quote Jimmy " The album sounds a little bit contained. It was a state-of-the-art studio, but there was no ambience. We had to take the front bass skin off John Bonham’s drums. Then we had to use a machine to create a fake ambience." You guys make have read the interview or it might be posted here already.
I remember