(2)Where a single sheet of paper, not being paper bearing being an impressed hundi stamp, is insufficient to admit the entire instrument being written on the side of the paper which bears the stamp, so much plain paper may be sub-joined thereto as may be necessary for the completing the writing of such instrument:Provided that in every such case, a substantial part of the instrument is written on the sheet which bears the stamp before any part is written on the plain paper sub-joined.
