Ok lets start to clarify for you.
Basically the NVQ consists of core units, H&S, Principles etc.
plus other units such as installation, testing or motor fault finding and testing depending on which path you are taking. Generally in industry Installation Electricians can work as Maintenance Electricians but not the other way round. If you are thinking you want to be installing circuits at some time then the Installation(buildings and structures) route is the one to go for. Currently the C&G 2357.
Copy this in to get more info or feel free to ask again.