This might be of interest, bit can I ask a few more dimensional details?
A- Vertical separation of the mounts?
B- distance form the corner to the cushion mount?
c) the angle of the bend?
not on pic - the overall width at the mounts - 0242 hints this has a taper, and I can't tell which of the mounts you have taken in Pic 0252
Alternatively, what was this designed to fit?
I am batting various ideas around re. a seat improvement, which currently is held in by a very inadequate method and has no backrest. . I'm thinking of going hinged and need to make sure the backrest will clear the squab when hinging. if this fits you may be about to save me a lot of faffing!