The version Leadfingers posted ("we surgeons have fun...") is very close to the one I used to do, and I lived in Bracknell, so he might have got it from me. However, I'm pretty sure I got it from Alan Holdsworth when I lived in Manchester. I've messaged Alan to see if he can cast light. A bit late in the day, I know, but I suddenly remembered the song today after several years of repression, and found this thread...