More poorly- disguised horror lurking in the rear seat back. The brushed-on underseal is a clue that this was a less than conscientious repair.
This area contributes to the lateral stiffness of a Mini’s shell, so needs to be strong. More welding!
In hindsight, I really should have just replaced the entire boot floor/seat pan. This is why you have the shell stripped before commencing repairs.
A small obsession 