I don't know about MAN, but in LHR, EK uses Tristar for Chauffeur and they text and call before just to confirm baggage pieces and timing.
EK Call Center (UK): +44 844 800 2777
MANCHESTER Airport Office (EK): +44 161 489 2488
Don't know the number for the chauffeur company since I don't know what company EK uses in MAN.