Thanks for your efforts mate. I altered it just slightly because there is a mobile cam close to home so easier to test out live.
; S P E E D C A M - C A T : 1
activated_speech="Mobile camera ahead."
skin_off_sound = "speedcam_off"
I hear spoken "Mobile camera ahead" just the once and (sometimes) "Warning!"
Once again skin_off_sound = "speedcam_off" is totally silent unless I have the skin activated. Audio files are in correct folder.
I usually use min_frc=1 although I do not understand what it does.