Service of bills for tax or notice of demand by ordinary post.

Notwithstanding anything contained in Sections 370 and 371 a bill for any tax or a notice of demand may be served by sending it by ordinary post with a pre-paid letter under a certificate of posting addressed to the appropriate person specified in Section 371 at his last known place of residence or business and in proving the service of every bill or notice so sent it shall be sufficient to prove that the matter was properly addressed and posted under a certificate of posting.