AH! Like the old orange Jubbly drinks that the shop would put into their freezer!
Showing my age here, who else remembers them?
@Kayfersmum First of all you can eliminate one seam, just cut a double length rectangle and join the short ends.
Tweek the length of the rectangle so that the seam (stitching line) goes through hearts/between two hearts.
Tweek the height of the rectangle so that the stitching lines, top and bottom, goes between rows of hearts.
If you do the necessary tweeks, the size might be a little bigger or smaller but the seams will be barely noticeable.