Well the car does indeed have a faulty throttle body. It was confirmed this morning by the warranty engineer. It will take the garage two hours to fit the part. The ordered the part in at my request for the warranty engineers visit two weeks ago. (This was the one where he found no fault as the garage had cleared all the fault codes in the computer!) I had to agree to get the work done even if the warinty would not cover it for them to order in the part. It turns out while waiting for the second engineers visit today, they sold the part to someone else! Ahhhhhhhhhhhh! So now no car until they get the part in - again!