the latest news is: after readiing some further info on replacing nozzles one of the posts said "Nozzle bedding in time " they said to drive for at least 30 miles.
this has been done and most of the knocking has gone, i still have the miss at idle on number 5 cyl. I have already ordered a new Injector, " seems folks dont have much good to say on these as they are now made in India. I will replace & report back with results.
i still seem to think the valves are not opening fully, easyier to replace injector first before removing camshaft to replace lifters.

thanks everybody for the help.

cheers.