https://www.naric.org.uk/naric/Indiv...uments/SoC.pdf
If you look at the example of statement of comparability, you will see the statement, that your qualification/grades are equal to GCSE grade C or above (if they are obviously). I've done mine earlier this year and they state that all the grades/pass on my certificates are equivalent to GCSE grade c or above. Hope that helps.