One of the things my locost failed the SVA was because the rear fog light lens wasn't vertical.
Does anyone know were I can get a triangular packing piece to bring the lens to the vertical

Some lights come with packing pieces but they're rarely the right angle to get it exactly upright.

I made mine. Cut two pieces of ply the same shape as the back of the light, glued them together in a V (with a spacer piece of wood at the top to get the required angled), filled the gap in between with lots of easy-sand filler, sanded it, sprayed it black, jobs a good'un....
Used self-tappers from inside the light into the ply and equally from the inside of the rear panel into the other side of the spacer to secure everything... (don't forget a hole for the wiring!!!)..
2 hours...

Make one is the best way then ul find it will fall off on return from a pass.

Failing that mine came with an angled mount so maybe theres one available for your type of light..

Just uploaded a pic of the finished article on my car to my photo archive. I attached the main body of the light to the ply packing piece before filling and spraying so it looks like it is one piece and meant to be...
Hasn't fallen off despite banging into it every time I go round the back of the car!! Really must remove it now SVA is out of the way!!!