12. Notices under articles 9, 10 and 11 must be in writing and served on an employer assessed to the levy by—
(a)delivering the notice to the employer personally; or
(b)delivering the notice to the employer’s last known address, place of business or registered office; or
(c)sending the notice by post to the employer’s last known address, place of business or registered office; or
(d)where the employer has notified the Board of an e-mail address at which the employer is content to accept service, sending an electronic copy of the notice to that e-mail address.