I meant Reg 7 of TSRGD.
I also can’t find reference to the variation of the length of the individual marks that make up the zig-zags lines. In the 1997 Regs, the marks could vary 1m to 2m. But now I only see 2m in the diagrams e.g. Diag 1001.4 (Sch 14, Pt 2, Item 52).
Funny thing is, in the Variants for this Item, it says :
“Each zig-zag line need not contain the same number of marks
as any other line, provided each mark is of the same length as the others”.
Why mention the length unless it can be varied?