I have abandoned the idea of a raft and gone with a brim. Seems to be a lot better but still not acceptable. I haven't changed any temp or speed settings from default but what I have done in CURA , on the advice of Ultimaker UK, is to change infill pattern to tetrahedral, support pattern and interface pattern to Triangles, the support interface thickness to 1.5 and the brim width to 7. New testing is underway. (soon going to need some more material)