Finally, I repaired the trampoline by using a upholsterer on Bartholomew Drive. His machine is heavy duty and he could restitch the thick material with ease (cost $30)
I also replaced all the lines used for securing the two separate pieces to the frame. It was an on going process, tightening the lines progressively each day until it is really tight and can hold my weight with ease. A loose trampoline will have the load less evenly distributed, resulting in localized hi-stressed areas.
Now it looks tidy and clean. Next job is to identify the part number of the standing rigging (side stays) and place an order for them online.