I have just posted the most recent copy of the Labour Party Rule Book that I can find, this copy is hidden in member’s net; I am unclear if it requires a login but the search engines have difficulty in finding it. I have also created a bit.ly short name for the LP’s version, bit.ly/uklabourrules17. This copy of the rules are the 2017 rules, presumably authorised by lab16.
And it seems you now need to read the Collins Review as part of the rules. My copy is behind the preceding hyperlink. I wonder if this is still true in 2016.
If you want to go back beyond Collins, there’s the 2013 Rule Book.
There is huge demand for the rules about the conduct of meetings; these are held in Chapter 15, here is a copy, LP Rules 2014 Meetings, Ch 15, as it says based on the 2014 version of the rules but I don’t think they’ve changed since then.