You could try this guy or maybe some local breaker. They'll probably want to sell a complete engine if it's good but someone will have one which will be knackered & will be only too happy to break. Otherwise try BMW, the engine is the same as that fitted to the 1998-2001 320d model though I believe the BMW uses some Pierburg parts whereas the Freelander uses Bosch. It's got to be worth a try though you should take your faulty bits in with you to compare.