Just found this as it qas linked to another topic.I used a 4motion tow bar with a swan neck.
A lot of chopping and strengthening the support
Then I made the parts you can see which slide up past the plastic in the middle and in between the exhaust pipe.
I work for a company who make HGVs so I have access to stress analysis tools so I could determine what arrangement of bolts that were needed.
As you can imagine, I had to use counter-sunk 12.9 grade bolts on the bottom where the pipes come past.
I will never tow anything heaver than a motorbike trailer with it but I engineered it strong enough if I needed to pull my box trailer with something else in.