I made a set of the wind deflectors for both my Sani and my Terrano.
I bought a strip of 1.2mm thick, about 120mm wide stainless steel. I then measured the length of the rear pillar and cut a piece from the strip to the correct length. Next I would cut the bottoms and tops to the same angle of the rear pillar and round the sharp corners and then bend the rear end of the piece of stainless steel plate over a 50mm pipe.
Together with the 120mm wide piece of stainless steel, I would have several pieces of 1.5mm stainless steel cut into 25mm strips to make mounting brackets. These brackets would be made the same length of the plate. The ends would be bent at 90 degrees about 40from the ends and from two I would make one adjustable bracket to bolt to the vehicle with 2.5 or 3 mm thick stainless cap screws.
These looked very good and people would think they were shop bought.
Here are some pictures of the deflectors on my Terrano and also one partial of the one on the Sani. Unfortunately I could not find any pictures of the deflectors on the Sani or the Terrano, showing the mounting brackets clearly. On some of them you can vaguely see the brackets, but on most you can see the stainless steel cap screws holding the bracket to the deflector.
On the Sani it had to be fitted to the door, because the door actually formed the rear corner of the vehicle. I could not mount it on the pillar, the door would not have been able to open past the deflector had it been mounted on the pillar.

- Wind deflector 1.JPG (106.25 KiB) Viewed 3867 times

- Wind deflector 2.JPG (211.82 KiB) Viewed 3867 times

- Wind deflector 3.JPG (46.82 KiB) Viewed 3867 times

- Wind deflector 4.JPG (208 KiB) Viewed 3867 times

- Wind deflector 5.JPG (150.6 KiB) Viewed 3867 times

- Wind deflector 6.JPG (261.95 KiB) Viewed 3867 times

- Wind deflector 7.JPG (233.63 KiB) Viewed 3867 times

- Wind deflector Sani.jpg (48.57 KiB) Viewed 3867 times