Have had few problems with my 2003 td6 and have scanned it and the live data @tickover shows 0rpm on all cylinders and injector readings of 0mm3 on all injectors.
Car has had new in tank pump,lp pump,fuel filter,all injectors tested and 4 replaced and recent full service.
It's now running slightly rough with bit of black smoke which gets worse when trying to drive car.has got me baffled now and any help from you guys would be much appreciated

Have you checked the crank case breather? if it's still the old style filter they can be prone to getting blocked and causing smoke issues.

Other than that if your still getting the misfire I would suggest that you get a compression test done, as you seam to have covered all other possibilities  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

It's highly unlikely that ALL 6 cylinders are reading 0mm3

It sounds as though the diagnostic is not communicating properly with the PCM

^^ 0rpm and 0mm3 on all cylinders should be 800 rpm for a kick off  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!