Numeracy and literacy question ?

Hi, I did my level 2 numeracy and literacy in 2007 at college, this was a certificate and was from City and Guilds.I have a Btec level 3 in Electronic Engineering with double distinction grade.I am considering doing evening GCSE classes and this would mean doing a AQA Math GCSE at 'A' and a WJEC English at 'C' test exam.I spoke to some tutors and they suggested I don't need to do the two GCSE as the level 2 are already equivalent to GCSE grade 'C'. However, other tutors suggested the opposite and that they are not equal and worth doing as it would improve employability.They also said there would be a 5 year time limit on the level 2 before having to resit them,is this true? My question is are doing these exams worth it taking my situation in consideration ?

Thanks