Right. Here goes....
It's established that points were awarded to the first 3 finishers in each class.
Sources:
https://btcc.fandom.com/wiki/1958_BSCC_Season
Alex Burnham's 60 Seasons book
Frank's website establishes the scoring system as 7-4-2 plus a bonus point for setting the fastest lap and the top 6 in the Standings as follows:
1. Jack Sears 48
2. Tommy Sopwith 48
3. John Sprinzel 47
4. Doc Shepherd 41
5. Alan Foster 40
6. Jeff Uren 36
http://touringcarracing.net/Pages/19...C%20Class.html