I am a relatively new AutoCAD 2008 user; in the office we have a standard  set of layers, when I import these into a new dwg file via Layer States Manager they all appear correctly named but without colours, lineweights and any other property - has anyone any idea why, and how may I avoid it?

Don't know exactly why is that happening to you.
Try the following: In the Layer Properties Manager (the LAYER command) press Alt+S to display the Layer State Manager. First in the source drawing create (New) and export your layer state - save it to a .LAS file. Then in the target drawing run again the Layer State Manager and click Import to load the previously saved .LAS file (do not use the .DWG option). The current layer status will be redefined from the LAS file settings.
You can find this in Tip 5994-->