Concerto no 3: cadenza by Reinecke in I
Concerto no 5: cadenzas by Beethoven (I) and Backhaus (III)
I presume he plays Beethoven's cadenzas in 1 and 2.
Now I have investigated the question.
He plays cadenzas by Beethoven in concertos 1 and 2.
In concerto 3 he plays as André writes Reinecke's cadenza.
In concerto 4 (Andrë writes 5, typo??) he plays a cadenza by Beethoven in the first movement but not by Beethoven in the third movement, might well be his own.