Right then, this may be useful to you all......or not....your choice.
If you do not know if a control is HF or Switchstart, get out your mobile, set it to camera, look at the light fitting [when on] through the viewfinder. If it is switch start then the lamp will 'strobe' in the viewfinder. if it is HF the light will appear normal. Unfortunately this does not work with iPhone 4
note....this method is fricking useless if the fitting does not work; so on reflection it is a bit of a carp piece of info really, sorry....... :coat