Seems 9-3s leak from the water pump quite commonly, I have since found out. And given the crazy time of year and the complexity of the job, I am actually going to pay someone to do this one. Not my usual style, but there it is. Thanks for the instructions and suggestions too gents. Looks to be a 'Level 4' DIY job from what I can see. The mechanic who is doing it said it takes him 7 hours, so I can only imagine how long I would be.