Sounds like you've bought a right can of worms, might be worth asking about parts cost in the Engine/Gearbox/Running gear section.
If your going to get it sorted i'd recommend becoming a member, then you can access the traders section, they all offer discounts for members, one of the traders sells second hand/reconditioned parts, so for £12 joining fee you could be saving a decent amount of money on parts and servicing.
Every year my membership fee more than pays for itself on oil & parts discounts.
Then again you never know, someone might be willing to buy it off you for £800quid.