N.S.B. members at the Maliebaan in Utrecht in 1940. Farwerck is listed as 20, Mussert as 26. When you start left and count every head going up and down, the beardless man in the middle is Farwerck and Mussert is indeed head 26.
Source of the photo.
According to the source, the photo is from September 1940. Later that year, Farwerck was worked out of of the N.S.B.