As you said you didn't have a problem I went home to try it from a different drive on a different Mac, same footage, new everything else, same problem!
My mac is up to date so latest QT and Adobe suite.
Just tried a Handbrake encode and same thing, as Final Cut exports, the tone remains! This is unbelievable.
Interestingly, when I export the footage back out of Premiere, the tone isn't there! It's just in Prem.
Anyone got anything else I can try before I spend two days editing with tone in my ear?

Thanks so much for the help so far.
Nige
I see/hear this outside Premiere Pro as well. I hear it in PotPlayer, VLC, Adobe Audition, Premiere Pro. The microphone used to record or the eletrical circuits in the camera (or both) did pick up some nasty electrical "noise" from some source in the room, probably the lightning. There are some very high pitched signals/tones there and they can be removed by using a Notch Filter.
If i in the Audio Track Mixer use the Lowpass filter and set it to 18000 Hz and then use the Notch Filter using the settings below and then wrap it up with a Highpass filter set to 160 Hz i get a decent result that you can download here: C0003.zip
