Dave that worked but not exactly as explained because the different versions of software... So I've updated and highlighted as per Inventor 2013
Top level Representations /Positional:
Create the positional reps required in the subassembly - In your top level assembly create a new Positional Representation and ensure it is Activated Within the top-level assembly. Then right-click the subassembly you want to change (in the browser) and select Override - Click the Component tab. Check “Positional Representation” and then select the Positional rep you want to be activated when the Positional Rep in the top-level assembly is activated.
Switching between the Pos Reps in the top level assembly will now activate the associated Pos Rep in the subassembly. Note that if you need this to work through multiple assembly levels you must set up this relationship between each level of the assembly (Can't override a Pos Rep of a grandchild sub from the top-level assembly).