Ford replaced part of the loom that feeds the glow plugs and checked them as that was what they thought was wrong? But sadly no it wasn't they kindly charged me nearly 300 quid for the privelage of this "fault finding and repair ". Then gave me some injector cleaner to pour in which did kinda solve the problem until the tank emptied then it came back! So I do think injectors are the problem. I will have to trust the diesel specialist.