You can also find a school approved to provide the Competency Based Modular Instrument Rating (Aeroplanes) theoretical knowledge in Standards Document 31.
As of 2026, there are now only 2 schools that are said to provide the Theoretical Knowledge. They are Caledonian Advanced Pilot Training Limited and CATS. Bristol Groundschool (BGS) has reportedly stopped taking new students for the CBIR (Competency-Based Instrument Rating) theory course