Just a late contribution to this topic.....
In standard form, the rear axles in Morgans move around a lot when cornering. In some cases, the leaf spring and the spring-to-axle mounting plate will come into contact with the inside of the chassis. It can also be exacerbated by the axle being slightly offset - Morgan's are hand-built after all! The extra weight of a passenger will only make matters worse.
Use a torch and shine it down along the inside of the chassis; you should see any signs of contact.
As per the advice from previous contributors,a panhard rod is a useful enhancement and will improve cornering. No longer will you feel the car 'lurch' into the corner following the initial turn-in. I bought one from Dave Rutherford in the early eighties and never looked back.
