I assume seat belt location and way they are fitted to car will form part of any review. After my Oulton crash (car 92) somebody told me that belt mounting points are more important than frame mounting. If the frame breaks the belts should hold you, if the belt mounts fail then you have major problems however good the frame. Appreciate some belts attached to frames at all or some points so in those cases focus on the frame.
My seat was badly broken at Oulton and I suspect the hip harness may have been at the wrong angle, the hip belts according to manufacturer sites I have seen state that they should be mounted as close to the line of the leg and hip as practical & at an angle of 45-60 degrees. Moving the seat more centrally while using the cars original belt locations at the B pillar may not be best location for instance. The belt mount locations in Car 92 crash were all fine.
Not much of a frame either if you look at the photos but that did hold being attached to plates.
The seat uprights also were bent on Car 40 at Snet I noticed like mine above - so the 'frames' seem to hold better than the uprights in all these accidents, maybe its by design the uprights are meant to flex.
The seat was not very straight afterwards.
I agree with Wayne and Pete amongst others that the driver should for safety reasons be more central if possible. If Car 92 had been left hand drive I doubt I would be walking very well today.
Reading Chris and Louis's notes is I am going to look at adding tube between the vertical roll cage behind the B pillar and the rear cage legs to brace them.
Also at CSCC scrutinner this year with my hybrid car they wanted to see roll cage bar between the feet running forwards (below the hip bar).
After being hit at Spa in 2015, we were very happy to have no injured driver, although the shock was on a left-hand drive.
This is due to the very good quality of the metal chosen for our roll cage (it folded under the push of the left door)

But we are also lucky that the shock did not take place 50 cm higher.

Consequently, during the construction of our new 2CV, for 2018 Eco Class 24HR race, we'll slightly raise the horizontal bar to the left of the driver, increase the quality of the materials, and be extremely careful on the points of attachment to the chassis.