Hi, thanks for the advice. I do have a multimeter, I have a compression tester for petrol cars with adapters, but I don't think it is suitable for diesel? I have never tried.
I know which inlet pipe you mean, I just wanted to be sure. Would there be no turbo involved if that is removed?
I don't think the starter has fried - that is because, on the first day I broke down I cleaned the EGR (thinking it was that simple), and started up, went for a 1 minute drive - the car ran rough. It stalled. After stalling / dying, it turned over as if it was impeded, very slow, sounded like a low voltage battery. So I sat and waited, then tried again and it came to life, so I brought it back to rest (where it has stayed).
After that, maybe a week later, I had unbolted the DPF and was turning the car over and it was turning over fast - as you would expect to hear.
I am going to disconnect the DPF again and find out the difference, to rule it out if anything.
Anyway, it is possible the starter has fried, but it isn't the reason it broke down, and after doing all this work it may only be one of the reasons that it is not starting right now. There was something underlying, as when it was started, it was rough, had very poor pickup from idle, and then would stall on me. Again, could be a fueling issue if not enough pressure is reaching the injectors.
Do the injectors still work if there is not enough pressure? How are they fired by the ECU?