Thanks Dawntreader.
I will head back down to the boat today and play with it again. What confused me was I was not getting 12v across the red and black connections but the data was powered. I then reversed what I had done and the ST60 system powered up after a min or two . I will play a bit longer before I get an expert to do it , "a man has got to know his limitations" Clint.
The instal of the MFD was made easier by Bavaria having supplied the power wiring for a chart plotter in that position already, nice, danka sehr.