You are correct there. You add 50 feet to your minima to take into account for PEC if your aircraft manual does not provide for calculations to calculate the PEC.
I am just a bit confused about the Area QNH that is given to by ATS. So, en route, I am supposed to set my altimeter to the Area QNH, and then when I am descending for my approach into the aerodrome, I set the altimeter to the TAF QNH? I would have thought the Area QNH given by ATS would have been more accurate...
