If within Administration > User Admin the user has their system role set to one of the apprentice roles; their hours will not reflect in the Workshop booking diary.
To ensure the user's hours are being pulled into the Workshop booking diary, you need to ensure the system role of the individual is set to 'Technician' within user admin for this data to be displayed in the booking diary.
Ensure the home location is set to the specific workshop department that technician works for.
Please note: Within the Technician Details Parameters screen, you are able to tick the 'Apprentice' option at the top of the screen - which will identify any technicians with any of the Apprentice system roles and use their data within the Time Analysis report; such as Utilisation and Productivity.