Series 3 Land Rover series 3 knock

hi, I have a series 3 2.25 diesel that has a slight miss when cold and a constant knocking sound. when started cold, the engine seems to be missing or poorly firing on one cylinder. it sends a shake through the cabin and a puff of smoke from the exhaust. after about a minute this stops. however there is a constant knocking sound as well. does anyone know how to fix this? thanks

Welcome to Landyzone, you could try slacking off the nut on each injector in turn and see if the knocking stops which could be caused by faulty spray pattern on injector , have you series or parallel heater plugs and are these ok , perhaps you could also video the noise on you tube and put a link on here