The Martha Grand National & Austrian Group 2 Racing

[Jon64]

The "Martha Grand National" was an initiative by the Osterreichring owners to create versatile races with a variety of vehicle categories to appeal to wider audiences. The 1970 race - held on October 25th - was a noteworthy effort, with Group 1, Group 2 and GT cars racing together in a 10-lap event. (Niki Lauda won his class in the Porsche 908/2). There doesn't appear to have been a race in 1971, and in 1972 it was a Group 2 event according to the late Frank de Jong. No Martha Grand National race is listed for 1973, but‎ on October 14 that year (around the time when the MGN had been run) the Osterreichring staged the "Zeltweg Saisonfinale" of the OSK Staatsmeisterschaft for Tourenwagen-Rennsport, which included a Group 1 race won by the BMW of Karl Pankl‎, and the "Ford Capri Vergleich" won by Lauda. Was this race the MGN by another name? In 1974 +1975 the MGN was a 12 hour race for Group 1 + 2 cars and wasn't part of the OSK Championship in either year.

I am particularly interested in the 1970 and 1973 races; although these are referred to in the statistics sections of Lauda's autobiographies, other than a brief mention of the top placings on Frank's superb Touring Car Racing website, I have never been able to find any contemporary reports. Can anyone cast further light on these or give greater details of what happened?