G`day .The Carnival has a K5 motor which is a varient of the KV6 on Landrover Freelander,Rover 825 .These engines only differ on The camshaft gears,which are totally different.The bottom end however is the same.Same block,same crank,same pistons.The ECUs might be different and might not be adaptable.A KV6 Motor has lots of things on the top end which you wont find on a standard Kia Carnival.
Oh you are in UK.The Sedona is a carnival.You have a K5 Motor.May you take some photos of your main wiring Loom connector in the engine bay.The one close to the brake master cylinder.