The compulsory subjects almost certainly included:
* English Language: This was and remains a mandatory GCSE.
* Mathematics: This was and remains a mandatory GCSE.
* Science: This often meant either a combined science GCSE or separate GCSEs in Biology, Chemistry, and Physics. The exact requirements varied by school and exam board.
Your school's statement that you only have two options to choose *after* those core subjects is plausible. Let's say the core subjects took up three GCSE slots (English, Maths and a double science). If your school offers five GCSE options in total (which was a common number), that leaves 5 - 3 = 2 choices left for you to make.
To find out definitively what you needed in 2012:
* Check your old school records: Your school should have records of the GCSE options available in 2012 and the compulsory subjects. Contact your former school's office.
* Look at old prospectuses: If you can find a school prospectus from 2012 online or in archives, it would list the GCSE options.
Without access to your specific school's records from that time, it's impossible to say for sure what subjects were compulsory and what were optional. The core subjects mentioned above are a near certainty, but the number of options you had beyond those depended entirely on your school's curriculum.