21. No election held under these rules shall be invalidated by reason of any misdescription or non-compliance with these provisions, or by reason of any miscount, or of the non-delivery, loss or miscarriage in the course of post of any document required under these rules to be sent by post, if it appears to the Returning Officer that the election was conducted substantially in accordance with these rules, and that the result of such misdescription, non-compliance, miscount, non-delivery, loss or miscarriage did not affect the return of any candidate at the election.