Whether to go 2003 or 2006 for a vehicle that did both events will really depend upon what equipment is still left on the vehicle and what can be easily obtained. For an authentic appearance either would be correct but the 2006 appearance would be as it finished the event and the later part of its history. Down to personal choice really.
Finding the correct equiment from either event is an expensive and time consuming trek.
I did have a quick look into the costing of getting the vehicle back to full spec and I think its safe to say I will probably be putting the decals back on and the floor on the roofrack and thats about it! BT52 OVJ - G4 Defender 110 Stage 3 Film/Comms vehicle fleet no. G4AUS04 vehicle no. 43