Erik
Many thanks for the hint, I ran it overnight using the Eterlogic VSPE and it ran without complaint, Really weird that my Eltima VSP Emulation doesn't run it quite happily, as this is the first issue i have had with it in a long number of years both professionally and for amateur purposes, Fascinating really and when I have more time i must run some tests to see if I can pin down the exact cause but in the meantime it's working fine so thanks again, I have ordered up a licence so I can run it as a service for simplicity.
Brian (OZ1CTZ), I now have the Waterfall display running reasonably to my satisfaction displaying about 70 KHz and outputting via the Skimmer function to MAP65 for monitoring (although there is a significant oddity in level sent to MAP65 depending on whether I am on 28 or 144) with narrow output going to WSJT-X for QSO use both via appropriate VAC channels.
Again thanks to both for the assistance and I have no doubt I will have a further number of questions
Regards
Jim, GI1CET