These are the two Certified Arabic Courses you can do in the UK, and the Exam venues and dates

Pearson Edexcel GCSE Arabic:

https://qualifications.pearson.com/en/
qualifications/edexcel-gcses/arabic-2017.html

Cambridge IGCSE Arabic :

https://www.cambridgeinternational.org/
Images/502848-2021-syllabus.pdf

Exams Entry Venues and dates

https://www.tutorsandexams.uk/