The standard letter rate changed to 'tuppence' in August 1920. The existing dual plate 2d Kangaroo could not possibly produce sufficient quantities. The Roo die itself was also worn out having already produced at least 3,500 cliches by direct stamping. So Harrison produced new quad plates with this design. Be aware, there was NO policy or intent to replace the kangaroo series, merely necessity as wear, tear, or demand took their toll.
Harrison altered the KGV 1½d die to make 2d KGV electros so, not surprisingly, the 2d electros have many similarities to the 1½d. They originated from the same die, were printed (usually) in blocks of four electroplates, and the plate layout for both is the traditional 2 pane, 10 rows of 6 without jublines.
Note also that there are two distinctly different manufactures for this issue
Also see Booklets