Astra 05 1.7 cdti won't start

[Busygizzy]

I need help!! I have my amazing astra that has never failed me (except for the usual starting motor etc) until now! I had the diesel filter and fuel pump changed end of December since then the car was intermittent starting. It would start every morning no problem but after it had run it wouldn't start for a few hours. I had alternator changed (garage said that was problem!) Problem carried on, now it won't start at all. Had it plugged in an it's saying ecu not found?? Only lights on the dash are car with spanner and battery light. Battery has been checked and starting motor. Any advice? I've looked into having an identical replica ecu built so I wouldn't need new keys/coding etc anyone done this? I don't want to scrap my car but can't afford the £500 for all new that the garage quoted me! Thank u in advance I'm pulling my hair out!