50.—(1) Any document which is required or authorised to be served on a person under these Regulations may be served on the person concerned—
(a)by delivering it to that person;
(b)in the case of a person that is a body corporate other than a limited liability partnership , by delivering it to their secretary at their registered or principal office, or by sending it in a prepaid letter addressed to the secretary at that office;
(c)in the case of a person that is a limited liability partnership, by delivering it to a designated member of the partnership at their registered or principal office or by sending it in a prepaid letter addressed to a designated member of the partnership at that office;
(d)in the case of a person that is a partnership other than a limited liability partnership, by delivering it to the partnership's principal place of business; or
(e)in the case of any other person, by leaving it or sending it in a prepaid letter addressed to that person at their usual or last known residence.
(2) Where a document is to be served on the occupier of any premises under these Regulations and it is not reasonably practicable to ascertain the name and address of the person on whom it should be served, or the premises are unoccupied, the document may be served by addressing it to the person concerned in the capacity of “occupier” of the premises (naming them), and—
(a)by delivering it to some other person at the premises; or
(b)if there is no other person at the premises to whom it can be delivered, by affixing it or a copy of it to some conspicuous part of the premises.