OK, maybe I have got the wrong end of the stick here
I'm drawing a straight line, measuring the true heading and then adding the variation (local to the vor).
but why would you want to do that? The compass rose surrounding a VOR on a VFR Map is already in degrees magnetic, not true. Is the BEL VOR located on an aerodrome? (Not got a chart handy at the mo) If so, it's probably not going to be right in the centre of the aerodrome. Draw a line from the centre of the VOR to the centre or EGAE. Where does the line intercept the VOR compass rose?
Also, how old is the chart/pooleys that you're using. Remeber the magnetic variation changes from time to time.
Edited again to say I dont mean to sound patronising