Sorry for delayed response, I didn't see this earlier.
I believe I do, so you just need the A4 sheet of low ink card backs?
I have a PSD template I made that creates the png and then combine the png pages into a PDF.
The card backs are here, which did you want on an A4 sheet? https://drive.google.com/drive/u/0/folders/13DpJxynNghj6zFXFJV0xinHhP8h2mmoT