Brennan is a millinery designer who formed a partnership with John Hemmes in 1955. Their line sold to retail outlets, later through an outlet in the Strand Arcade, Sydney after 1957 where they sold hats and later, fashions. In 1959, the "House of Merivale" was launched offering adventuresome ready-to-wear fashion. A menswear line "Mr John" was also available. Hemmes (b.1931) died in 2015.