There appears to be a difference between SD (or perhaps British?) and American /International /ICAO terminology. Apparently:
SD "track" = ICAO "course"
SD "course" = ICAO "heading"
I can understand that with UK roots and a large UK user base, SD had chosen to adopt UK terminology.
However it can be confusing for those having been trained, and used to flying, elsewhere.
I doubt there is any answer to this.
Comments, anyone?
Volare...oh oh...cantare...oh oh oh oh

Bennett's 'Complete Air Navigator':

'Course is the direction in which the aircraft's fore and aft line is pointing expressed as degrees (as a three figure group) measured from the True Meridian, Magnetic Meridian, etc. In marine navigation the term 'course steered' has the same meaning, and in American aviation 'heading' is generally used.

I wouldn't argue with Bennett !

Maybe heading could be regarded as an instantaneous figure and course steered an average heading.

The heading can vary a lot in rough weather (at sea or airborne) while attempting to steer a course.