(1) Where an instrument creating a power of attorney is signed by direction of the donor it shall be signed in the presence of the donor and of another person who shall attest the instrument as witness.

(2) A power of attorney is not required to be made under seal.

(3) This section is without prejudice to any requirement in or under any other enactment as to the witnessing of powers of attorney or as to the execution of instruments by bodies corporate.