whats the best way to deal with the heading questions? Just visualise a compass or do the maths?
I personally find it easier to visualise the compass. Just memorize (or remember, in case you're already familiar with it) the 4 basic headings (North, 360; South, 180; East, 090; West, 270) and left/right turns on each one.
So, for example, if they say you're heading East (090) and you turn right 90 degrees, it should be immediate that you're now facing South (180). 45-degree turns are also common, so I recommend knowing this (clockwise): 360, 45, 90, 135, 180, 225, 270, 315, 360
Cheers!