Minty,
Headlights are on full time as standard on the modern bikes.
As for remapping, they break into the ECU , regardless of what one it is, and as they do it directly to the ECU you do not need a power commander. Power commanders are so last decade, remapping is the only way to go. A couple of places can do it and well known for doing good jobs, unfortunately not in London. I've used CJS Racing (
http://www.cjsracing.co.uk/) near to Bath for a couple of my bikes (1200 Multistrada & 1100 EVO), also BSD Performance based in Peterborough (
http://bsd.uk.com/).
I'd say CJS is better because he creates his own computer models where as BSD buy there's in, but both are very good.
With Dyno time & the work, you're looking at about £500, plus a tank of fuel and the getting there etc, and the hanging around for 3 or 4 hours.
It will improve power slightly, but the more important thing is the smoothness it creates all the way through the engine.