(b)except in so far as it requires a prospectus to be dated, shall not apply to the issue of a prospectus relating to shares or debentures which are or are to be in all respects uniform with shares or debentures previously issued and for the time being dealt in or quoted on a recognised stock exchange, but, subject as aforesaid, this section shall apply to a prospectus or form, of application whether issued on or with reference to the formation of a company or subsequently.