Check the fuse for the alternator, because for an alternator to work you have to suply it a 12v feed (the little wires) k11's have issues with the connectors on the fuse block corroding, also does the battery light illuminate?
Worth a try, only other thing I can suggest off the top of my head is was it raining or anything as the ecm's often get water dripping down into them from poor sealing firewall. Check ecm for corrosion internally lol. Although ear muffs sounds like a way easier better plan :p
The reason there is no codes is because your using a generic code reader, some of the nissan specific codes are not shown on generic ones. Id advise getting it checked by a diag computer peferably by main dealer
Im in a main dealer college, but in my opinion you learn a whole lot more in a workshop, the scrapyard sounds like a very good start. I started helping my mate build banger cars for racing. Just ask around at local garages and speak to the old techs lol :p they know way more than any college tutor.
the front cross member isn't MOT failable, and doesn't really do that much apart from hold the radiator, the other cross member that only stabilize's the engine. no real weight on it. i really wouldn't worry about it unless its pretty much fell apart
on the vast majority of cars they have something that's called chassis ground, which means that the negative off the battery goes straight to the car body meaning that all the bodywork is earthed. so you can pick up an earth off most bolts and screws, as the dashboard has a earthed metal frame...
all looks to be pretty good, it is bottom left ones, if you turn the ignition on itll do a bulb test, which just turns on that little red led, then short the two wires for at least 2 seconds, after removing link, it should flash five long five short which is code 55 which means its not the...