I have a 2005 Peugeot 308, with heavy mileage, engine light is on so needs a new catalytic converter in short - mechanic said it might not be worth fixing. This is second catalytic converter in space of 12 months. Central locking is operated through door with a key and there's something up with the door, locks sometimes or won't let you in other times, mechanic mentioned something about a clasp gone but would have to strip down to see. Is it worth my while getting it fixed? Am tempted to scrap and trade up as NCT in feb and no hope of it passing without serious work done?