Driven the car around the "test route" this evening and wow, what a noticeable increase in power and responsiveness. I will have to be careful until I get used to the engine characteristics but wheelspin in first and second is pretty good.
Oh no! I took a gamble with the water pump and it hasn't paid off. A tell tale weeping of water from the pump says it's got to come out and have the seals replaced.
Still, after 4 days swapping engines it should be a piece of cake.