Domestic Hot Water outlet pipe F 30 E Saun Duv?

I have a pin hole leak on the plastic connection piece between my hot water outlet pipe and the heat exchanger in my F30 E combi, what is this made of as most glues, fillers, say glues plastics except PVC PTFE UPVC etc failing this does anyone know the part no as getting thru to SAUN DUV cust serv is more expensive than buying a new boiler