Well installing wasn't fun at all! In the end I had to end up using a G-Clamp to hold the adapter onto the engine block so that the thread of the hollow bolt could actually grip onto the engine block. Not fun at all, so I made sure that I tightened this nut @#$@ing hard as I did not want to journey down this path again.
You will notice in the photos some oil on the floor and near the allen key bolts on the adapter this is because they were not tight enough, so before you install yours make sure that you tighten these as much as you can, as this is a b@#$ of an area to get to with tools after you have mounted the adapter. If mine keeps leaking i might even have to some some high temp tape to use on the allen key bolt threads just to create an air tight seal, but I think this is solved now.