Hi Jennifer,
Part-Time Fee Grants for students in Scotland can be used to cover part-time or full-time study in an academic year (1 August - 31 July). This is because although full-time study is permitted, The Open University is considered a part-time learning institution.
You can only make one application each academic year so ensure you plan your study. You can find more details in the Help Centre article which I am linking you to below:
Part-time Fee Grant: Scotland | https://help.open.ac.uk/part-time-fee-grant-scot
I hope this helps.
Kind regards,
Neems