Traced a water leak on my saph back to one of the core plugs on the exhaust side of the head so a new plug is needed.

Anyone got any tips on how to remove these? Looks like it would be easier with the manifold removed, however I said to myself last time that I would never do that job again with the head on/engine in the car!

Hopefully I can just remove the downpipe for access, here is a pic