On Friday I had my first ride with the new camera and bullet cam etc. I placed the microphone that came with the kit inside my tank bag with the camera and the results are patchy at best, down right crap at worst

It sounds like wind noise but not sure how that one works when it is inside the tank bag, maybe it is just vibration through the fabric of the bag against the fluff around the mic?

So where does everyone put their mic so that you can hear the exhaust and engine nicely but you don't get any crap wind noise or saturation of the sound channels?
Try wrapping some fabric tape around the mic and putting it back inside the tankbag. Like the white serrated tape used in hospitals and clinics.
If that isn't enough, try another layer or two of fabric tape. That ought to muffle it enough.
Do you already have one of those foamie covers on the mic? I f so, I'd put the tape on first, then the foamie cover next.