BMW 3 Series air lock, also missing part

just got the head gasket replaced, now i have an air lock that the person who repaired the head gasket didn't bleed the water system, left air lock in the system, now discovered that their is part missing from the head block to the the manifold that also attaches itself to flow flush pipe parallel to the head block, i can only describer were it sits, but unable to say what part it is, as the person fixed the head gasket didn't put the part back on in original placed as found before work had been carried out, did ask on many occasions but so far no a reply.