Hi can anyone help?

I have an 06 ford focus 1.6tdci 90ps which turns over but will not start.

I bought it with a seized engine due to a wack to the sump which damaged the oil pick up. I then sourced a secondhand engine as a replacement. It was a complete engine with diesel pump and injectors.

Once I completed the engine swap found that the engine would not start. I was then told that the injectors were coded so I removed the injectors from the original engine and then the replacement engine except for one which seems to be stuck, it is the injector nearest the timing belt (cylinder 4?).

After days of trying to remove the last injector without success, ( I tried soaking it in wd40, coke + cilit bang, levering it and pulling it with a large slide hammer), I decided to change the injectors that I could making sure that they go back to the correct cylinders to then start the car on 3 cylinders and hope that the 4th will free itself. The car will still not start, I have checked all of the fuses and before I replaced the injectors I checked for fault codes using a reader that only does engine codes.

Any suggestions? Sorry for the essay but the more info I give the more chance of help!

Thanks, Dan.