How does one change British sailors to selected items instead of random because I have put the items I want for them in the source code for NW but I can't work out how to change their weapon selection from random to eg itm_french_dragoon_musket
That won't work.
The random weapon selection thing is in strings and scripts. If you want to remove it completely remove it from scripts, or you can change the string to whatever weapon you are using for that class.
Not quite true - "Strings" just contain lines of viewable text (i.e. the text seen on the menu buttons, in singleplayer text dialogue, etc...). Anything in there will not have an actual effect on the code, only on what you read inside the game. The actual randomisation code should be in Scripts, as you said.
FYI MadManYo, you won't be able to use that module on a server running NW - it'll kick you for cheating if you do. The mod will need to be serverside if you want it to work.