Hi, Part exchanged a vehicle for a 3.0 V6 Sport pac X-type jag. Huge knocking noise from engine after a months ownership. Still under 3 month warranty, thank God! Got lifted by AA to garage that I had car from. Owner very, very good. Met me and took vehicle, no questions asked and gave me a courtesy vehicle. That was on the 12th November. Everytime I phone I get different reasons/excuses why the engine has not been fitted yet. Was supposed to pick up today (latest info) phoned to confirm this morning, car will not be ready until Wednesday. What can I do? (Still have courtesy car).