If i am overtaking on the right most lane (be it at 110 or >160km/h), and when there is another faster car approaching from behind, i shall turn on my right indicator to INDICATE that i am overtaking first, then i shall turn to the left or middle lane once i am done overtaking. And the faster car can overtake me.. real simple and easy to follow rule.
So, what happen even with the 'courteous' way above, the fast approaching driver flash his high beam like crazy? What i shall do is stick to my right lane with the right indicator, and then move to the middle lane when it is clear. I am not risking my safety just to turn to the left and let the IDIOT pass me. All he need to do is wait for his turn and then overtake. SIMPLE. Of course unless his car brake not effective..(or maybe do like the olden days driving, wind down your window and wave your right hand up and down, to give a clearer message that you are overtaking !! )
Well some might not agree with me, but i think, this is a softer approach, give in and be a defensive driver..
Cheers