If your car is not EC Type Approved for towing then it was illegal to fit the towbar. But the 2011-2014 Focus is rated to tow 700kg - 1500 kg so that doesn't figure. I can't tell you if the item in the manual is because of the gearing of the Econetic, or because fitting the towbar necessitated cutting the Econetic rear valence. If it's the gearing then you could be in trouble because the dual mass flywheel and clutch of the model has been failing, largely due to failure of the clutch slave cylinder and Ford dealers quote £1600 to replace DMF, clutch and slave cylinder.