(1) Without prejudice to section 18, where -

(a) the donee of a power of attorney executes, as transferor, an instrument transferring registered securities, and

(b) the instrument is executed for the purposes of a stock exchange transaction,

it shall be presumed in favour of the transferee unless the contrary is shown that the power had not been revoked at the date of the instrument if a statutory declaration to that effect is made by the donee of the power on or within three months after that date.

(2) In this section "registered securities" and "stock exchange transaction" have the same meanings as in the Stock Transfer Act, 1963.