The ITI (Institute of Translation and Interpreting) is the UK professional body for translators. The ITI membership exam is different to educational exams in that it is a post-experience exam conducted under real-world conditions. Even entrance to the exam is restricted to translators with five years of full-time professional translation experience, and the marking standard is extremely high. So passing this exam, and becoming a qualified MITI, is a very positive reflection on Mark's ability.
Mark also has an MA in Translation (and he tells me that he also has a Safer Swimmer certificate from when he was a lot younger!).
I hope you will join me in congratulating Mark.