So a couple of weeks and a lot of fiddling later.....

A new optical lead connecting the tv to home cinema has worked a treat, now sounds great with no sync issues.

Using the calibrated settings as a starting point (thanks again for the link), colour, motion blur etc now all much better, I'm now quite happy watching sport in either HD or SD & everything appears much more 'natural'.

Old Sony DVD & Humax PVR now all linked up fine & performing well.

Bottom line, a very good TV so long as you can feed audio through other equipment & are prepared for a lot of trial & error to get the screen settings right.

Thanks again for pointing me in the right direction.