You have to use your front fog lights with you sidelights is the advice i recieved from a police officer who stopped me for this. Apparantly using them with dipped beam or full beam lights is illegal. They are there to light up the road underneath bad fog so that your main lights don't just light up the fog. Due to this your front fog lights should be used even less than your rear ones.
I personally don't see what the fuss is about them I don't find them particularily dazzling when other drivers use them. And i think they light up the road a little bit better if you don't have HiD's. Which are quite dazzling when your travelling the other way up a road, but completely legal (and nice!).
Sorry, not meaning to offend, but this is utter 'dangle berries'....
Fog lights are for use in fog or falling snow or other seriously reduced visibility, taken to be 100 metres or less.
They are used with dipped beam lamps, not side lights. Any other use is technically unlawfull.
As to dazzling, the headlights are set to produce a particular beam pattern so as to avoid dazzle to oncoming motorists. Fog lamps do not have the same MOT-able characteristics other than if fitted, they must work. Only caveat to that is that ANY lamp fitted to avehicle must not cause 'undue dazzle'.
Front fogs are designed to light up an area immediately in front of the vehicle and do not have any significant 'range' unlike auxiliary headlamps or front spots which operate in conjunction with the main beam.