If you pass the CPL Skill Test on a MEP then you'll get both the CPL and the ME class rating. However, you must complete, separately, the CPL course, the MEP class rating course and the IR course (for minimum course hours see part-FCL); the only concession is that the Basic Instrument Flight Module counts for 10 hours towards both CPL and IR courses.
On another point, the UK CAA still individually designates examiners for all CPL skills tests and initial IR skills tests where the applicant holds a UK issued licence. They will not designate an examiner from the school where you have trained and may well not designate a local examiner, even if he's the most 'convenient' choice.