Many times, in UK legislation, the structure is of numbered sections, like 1., 2., 3...
Sometimes a subsequent act will insert sections that append lettered suffixes to the numbered section identifiers that precede their placement position within the act being amended, so that you might easily end up with sections 1, 1A, 2, 3, etc., which is also very sensibly understandable.
Other times, one finds added sections that add a Z before the A/B/C, etc. So you may get 1, 2, 2za, 2zb, 2zc, 3, etc. Obviously these are just section enumeration conventions, and could just as easily be entirely arbitrary subject to the whim and caprice of Parliament, but I assume that there is a discernible formula and pattern to them, and I wonder what it is. What is the significance or motivation for the convention of adding an additional 'Z' to inserted subsections?
As a corollary, what general procedural codes exist to guide (or bind) the parliamentary legislative draftspeople? Surely there must be style guides that they are bound to follow. What are these, and would they have the force of law?