Wow that would be a major, major downer having to buy a new ECU, hope when you get the next one fitted the car is okay otherwise clearly Alfatechniq or Autolusso are in for a serious shelling whether it's their fault or not.
Your first line in the original post was "Just to begin, i've learnt a huge amount about my car from the posts on here, really pleased there's a place like this to come to"
You gotta remember this and not get too down about your Alfa playing up a bit or the advice you've been given. It's cost you a bit, but it's still really cheap motoring and you shouldn't have to worry about your crank sensor failing in your ownership. You know there are Guys on this site that go well out of their way to try and help fellow Alfa Romeo owners and they have personally saved me lots of money by giving me the confidence and knowledge to do jobs safely. Some jobs I don't feel I could do safely are however left to the Pro's.
I've thought of a few bits that Guys on this site have enabled me to do.
Coilpack failure on my V6, diagnosed, stripped down the many connections, sorted fault, new plugs etc, sprayed coil covers.
How to clean MAF, saved me buying a new MAF after fault code on both my Alfas.
Reset electric windows
Refurb and refit steering wheel on GT, gaitors, dash/console, facelift trim on 156.
Windscreen wipers on 156 stopped working, stripped motor down, sorted.
One cooling fan not working on 156, new sensor, sorted.
Headlamps bulb change.
Sorted air intakes.
Remove roofrails, refurb, refit
Loads of suspension issues learned about, sorted by pro's however.
oh and CRANK SENSOR
There's been a few more little jobs I'm sure. There's also a few bits that I never would've felt the need to do if it wasn't for this site, so I've lost money there
I think of my Dad a few years ago under my 16V 33 with the subframe dropped, fixing some stuff up for me. If this site had been going while he was still alive, he'd have loved it and probably saved himself a lot of time and me a few rollockings for not helping him work on my car.
Stick with your Alfa, any car could have the same issues and please just keep transporting Tanks to the battlefield, don't FFS get in a Tank with live ammo