I wouldn't advise connecting straight from light hole to airbox. If you get alot of water into pipe (lots of rain or driving through big puddles) then you could end up flooding the airbox/engine. However, you could put a drain hole in the bottom of the airbox or, like I have done, make sure the pipework runs uphill to airbox (I have ducted up from gap in front bumper)
glue it maybe?how would we stand with the MOT it one of the mainbeam lights were missing?would i have to put it back in?