Wee update - added the aero underbody parts today and changed the oil and filter, and put on a short plate.
So far, I am not convinced the aero underbody mods will help with comsumption but we will see. What was noticed when fitting them;
1) The sump shield never clicked in to place like the original item
2) The stone protector guards needed trimmed to go round the bolted fittings for the handbrake
3) The middle shield needed trimmed to clear the 3" Milltek