Hi Stephen. A good question - we checked with the relevant Curator here, and they said that they would've assumed passports were needed, but in many circumstances the individuals wouldn't have had an existing passport prior to the migration process, so the question is whether they got them specially done to migrate. Wives and children may have been listed on the husband’s passport but women also certainly could have their own.
Our collections hold a couple of application forms regarding the application for UK passports in the 1950s-60s such as this, which refers to both joint and separate passports for women. People also had to surrender their British passports for 2 years upon arrival, so it might be also worth the enquirer looking for a certificate of identity which was given in exchange for a passport.
We hope this helps, and best of luck with your research.