Leaking inlet manifold

Hi guys. I am losing coolant thru the inlet manifold on my mk1. It looks like it is coming out of one of the water jacket / welsh plug. How do I fix this? Is it easy enough to fix?

You'll need to remove the manifold to see if it's just leaking or corroded, although if the coolants been changed regular this should not be the case. A local machine shop should be able to replace it in a couple of mins for a few pounds.