I have trial fitted the rear wings to my car and it seems that there is no direct fixing possible to the chassis, how have other people fitted them?

I bolted mine to the fibre glass side and rear panel. I could not think of any other way. They have both stayed on the car so far.

Jim

Mine are attached the same way using M6 screws with spreader washers and wing beading between the arch joint and the panels.

Mine were also still attached when I had a look 10 minutes ago

You can rivnut to the bottom chassis rail, the tube you rest your arm on and the top shock turret, the rest do as mentioned.