I have made some progress. In the swapping of port choice in Omni-rig set up and checking that the radio was set to the same baud rate I had messed up the radio RS232 settings AND the port driver I am using doesn't like the USB3 port the hardware was plugged into. When I moved it to a USB2 port and set the radio to be the same as the Omni-rig settings I found the radio was connecting when Port3 was selected.
Now I just need to tweak something to sort out a noise band which appears in the centre of the display and find out why whole waterfall display seems to be mirror imaged around the centre noise band. I suspect that the sound card in the PC is not keeping the left and right channels fully isolated, ie there is some mixing of the audio channels to help with mono sound tracks. The audio driver user interface doesn't have any options for this, it seems to be pretty dumbed down like much stuff in Win8.1 (like no ports in the device manager listing).
Andrew.