it had a new fuel pump, preasure regulator and fuel filter and housing a year ago and has been running fine, but now takes takes a lot of starting the pump is quiet i have replaced the filter and housing again with genuine partsand preasure regulator, no oil contamination at ecu, local land rover garage told me it was injector o rings, i replaced them and the copper ones still no difference, i was then told to regrind injector seats and replace o rings again (both times with genuine parts) still no difference and i have also replaced the injector harness genuine, system bleeds up very well it works fine for a couple of starts sometimes a day or to then starts playing up again. please help

First, I would suggest introducing yourself in the relevent section.

Next I would suggest using the search function.

Then I'd try the CKP sensor.