I failed my UK Class 3 colour vision test

I got offered a place as a trainee air traffic controller for NATS, but at my medical a week ago I got 5 wrong on the Ishihara test and a score of 3.1 on the CAD test, which from what I can tell is outside the limit. Everything else was fine.

My case has been referred to the CAA but I haven’t heard since, is it possible I can still get my class 3 medical or to retest? Or can I just never become an ATC? Has anyone else been in this situation?