from Monash website:
You will meet the Monash English language requirements if you have completed British GCE schooling.

You must have successfully completed:

British GCE O-levels and obtained a grade C or better in English, within 24 months prior to your study commencement date, or
British GCE A-levels and obtained a grade C or better in General Paper (A/S level), within 24 months prior to your study commencement date, or
University of Cambridge GCE O-Level 1119 English language with a grade C or better, and have subsequently completed A-levels. A validity period of three years from the date of exam taken applies.

i believe the last one applies to you