Roofrack mounted lights would only be illegal if wired in to operate with high beam, by my reading of the regulations. If questioned, the owner would refer to them as work place illumination lights, specifically mounted away from the front of the vehicle so as to not be confused as driving lights.
I;m with you BJ, having a light bar on your car is not illegal ,using it on the road is, just like so many other mods we all have, Wire it up on a seperate switch marked "offroad lights" or "worklamps"and when pulled over you should get no grief , even pull the fuse out. As for people using them on the road ,Well thats a different story.
Interestingly my new trition has a factory rear difflock , when it's engaged the ABS stops working and the dash light tells me that I have no ABS. I am sure I have read somewhere that modifications that effect saftey features are illegal. The way they prob get around this is that the owners handbook says "for offroad use only" . So if I used my difflock onroad (I know you never would but bear with me) my car would be illegally modifed as I would have lost a saftey feature of the car.
My point is that if it is designed for offraod use or worklamp use, then use it in that fashion and you will have no probs , but if you are, as others have said a white light warrior then you might loose some $$$.
Have a look at most lighting catalogues , Driving lamps are listed , then "worklamp" is the term used to cover led lightbars. the maunfacturers know the laws and the product discription is the answer , a worklamp is a worklamp and a driving light is a drivinglight , and I'd be pretty sure a magistrate would see it the same way if push came to shove.
but where led lighbars are concearned the cost of the damm things is the real offence IMHO LOL
Jet