Not sure about the access for the N62 but with the M62 if the mechanic lifted the engine instead of removing the radiator to get to the alternator then the #1 step would be to get a new mechanic. That said I have the original headlights on my pre-facelift and all of the tabs are fine and no more brittle than one would expect. Sounds like someone didn't know what they were doing and butchered your housings whether by hitting them or overtightening and snapping them.

__________________
Again Daily Driven SC'd 4.6iS, whats the point of having a sweet ride if you dont use it all the time.