Would every fleet carrier receive a defensive light carrier?

Would each large fleet carrier be assigned a light carrier for fighter defence?

No. The Royal Navy would need the light carriers for too many other station, reconnaissance, and support duties.

A dedicated defensive light carrier might let a fleet carrier concentrate its air group on strike missions. The Royal Navy would still have too many other demands on each available deck to make that arrangement standard. The service discussed multi-carrier tactics between the wars but entered the Second World War with its carriers scattered across numerous commitments. Additional light carriers ease that pressure without creating enough surplus for a permanent one-to-one pairing.