More ny luck than judgment I have resolved the issue, at least now we get sound from the front panel jack.
Here was my fix, Control panel/sounds/ click on speakers, and make them a default. hey presto sound at both front and rear.
I put this down to a Realtek problem, as surely this should be the deafult anyway? Frustrating as had been working on this for 2 days.
Both HD & AC97 are now working - HD is now left as the fitted option.