So decided going to replace the seals on injectors 1-3 now as well, the car smokes after being sat for long periods (6 hours +) which would suggest to me diesel is leaking over that period. Waiting for the seals kits to come. Also going to reset the injector last to try and smooth out all the injector figures and going to put a 1litre can of diesel purge through the engine.
Also going to replace the glow plugs as not sure when they were last done if they ever have been, clutch release bearing and Valeo SMF kit have also turned up.
Also check the harness (or bridge as it’s called) - I had error code a few years back and tried to change out glow plugs cold………snap, snap
Managed to get them out and replaced only to find out it was an issue with harness
Changed that out and been fine for years