after much investigation and research i went back to basics and with the aid of a degree wheel and dial gauge i found that the cam timing was retarded
so being able to temporary advance it on the adjustable sprocket it cured the problem. so the customer agreed for me to strip it.When stripped i saw part no on the pump end it was a BGA No so i went online to their catalog and found that they didn't list a cam for BKC engine codeso i called them and they said the reason was a superseded part No and that one fitted, the customer contacted the garage that fitted it and they basically told him where to go.Anyway i fitted a kit obtained from Victor reinz that matched oe part No(which was steel instead of cast that i removed)timing is spot on and problem resolved,the customer is taking up the issue with BGA..... So beware thanks to all for help and info